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Shengwen Qi
Institute of Geology and Geophysics, Chinese Academy of Sciences

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Preprint content
Published: 03 August 2021
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With the development of human society, mega engineering projects of removing the tops of hills to infill valleys began to appear in the loess region. The thickness of the manual filling compacted loess can reach tens of meters. For such large-scale construction projects, studying the properties of compacted loess is essential to ensure the safety and reliability of land creation and artificial infrastructure. In this paper, the specimens from two exploration well profiles were carried out to study the physical properties of natural loess and compacted loess from the Loess Plateau. Here the natural loess selected was deposited in old ages (Q2 and Q1) and had strong stability. The natural water content, dry density, specific gravity, liquid limit, plastic limit, plasticity index, clay fraction, silt fraction, sand fraction, compression modulus, and permeability coefficient have been determined. Statistical theories such as t-test and correlation coefficient checks were used to describe the difference between the two kinds of loess, and the degree of correlation among various indicators. Besides, 14 groups of exploration well data in 8 studies were collected. The variation of natural water content and dry density with well depth was analyzed to supplement the existing data. Results have shown that the manual filling compacted loess is significantly different from the natural loess. On the whole, the liquid limit, plastic limit, plasticity index, clay fraction, silt fraction, sand fraction and compression modulus of the compacted loess are smaller. And compared with the natural sedimentary loess with strong stability, it deforms more easily. The difference of compression modulus between the compacted loess and natural loess is mainly controlled by the dry density and the particle composition. Moreover, the heterogeneous level of the manual filling compacted loess is greater than that of the natural loess in the horizontal direction and smaller than that of the natural loess in the vertical direction. Under a combination of external hydrologic conditions and dead weight, the compacted loess will become more stable.

ACS Style

Linxin Zhang; Shengwen Qi; Yongtang Yu; Yaguo Zhang; Zhiqing Li; Xiaokun Hou; Lina Ma; Yu Zou; Songfeng Guo; Jianbing Peng. A Comparative Study On The Physical Properties of Natural Sedimentary Loess And Manual Filling Compacted Loess. 2021, 1 .

AMA Style

Linxin Zhang, Shengwen Qi, Yongtang Yu, Yaguo Zhang, Zhiqing Li, Xiaokun Hou, Lina Ma, Yu Zou, Songfeng Guo, Jianbing Peng. A Comparative Study On The Physical Properties of Natural Sedimentary Loess And Manual Filling Compacted Loess. . 2021; ():1.

Chicago/Turabian Style

Linxin Zhang; Shengwen Qi; Yongtang Yu; Yaguo Zhang; Zhiqing Li; Xiaokun Hou; Lina Ma; Yu Zou; Songfeng Guo; Jianbing Peng. 2021. "A Comparative Study On The Physical Properties of Natural Sedimentary Loess And Manual Filling Compacted Loess." , no. : 1.

Original paper
Published: 17 May 2021 in Bulletin of Engineering Geology and the Environment
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Rainfall-induced shallow landslides (i.e., the depth of the failure surface is less than 5.0 m) have been widely investigated in the literature. However, the relationship between water infiltration and deep-seated soil landslides (e.g., > 20 m) has not been fully understood. The paper presented here aims to investigate the cumulative influence of infiltration on the stability of the slope with a thick unsaturated zone. The Yanlian landslide induced by the steam released from heating pipelines of an oil refinery is introduced. The original slope has an unsaturated zone of 45 m. Field investigations have been undertaken to obtain the geological and morphological characteristics of the landslide. Triaxial shear tests, soil–water characteristic curves, and permeability measurements were carried out to achieve the mechanical and hydraulic properties of the soils. Besides, numerical simulation was adopted to investigate the spatial and temporal variability in pore water pressure within the original slope. Variation of the slope stability associated with the cumulative infiltration was documented. The results highlight the cumulative influence of infiltration on the hydraulic condition of the slope and the associated variation of the slope stability. The hydraulic condition reaches a dynamic equilibrium state (i.e., stable groundwater table, constant water flow in the unsaturated zone, similar outflux to influx) under cumulative infiltration conditions. Disturbance of the equilibrium state (e.g., irrigation, climate change) will cause the hydraulic condition to transform into a new equilibrium state. The results presented here are helpful to understand the cumulative influence of infiltration on the deep-seated soil landslides.

ACS Style

Xiaokun Hou; Tonglu Li; Shengwen Qi; Songfeng Guo; Ping Li; Yu Xi; Xianli Xing. Investigation of the cumulative influence of infiltration on the slope stability with a thick unsaturated zone. Bulletin of Engineering Geology and the Environment 2021, 80, 5467 -5480.

AMA Style

Xiaokun Hou, Tonglu Li, Shengwen Qi, Songfeng Guo, Ping Li, Yu Xi, Xianli Xing. Investigation of the cumulative influence of infiltration on the slope stability with a thick unsaturated zone. Bulletin of Engineering Geology and the Environment. 2021; 80 (7):5467-5480.

Chicago/Turabian Style

Xiaokun Hou; Tonglu Li; Shengwen Qi; Songfeng Guo; Ping Li; Yu Xi; Xianli Xing. 2021. "Investigation of the cumulative influence of infiltration on the slope stability with a thick unsaturated zone." Bulletin of Engineering Geology and the Environment 80, no. 7: 5467-5480.

Original paper
Published: 11 May 2021 in Landslides
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Qinghai-Tibet Plateau is one of the most seismically active aeras of China and rock mass structures or geological structure are also complex here. Earthquake-induced geological disasters are occurred frequently in this region. Among them, plane failure is often generated on bedding rock slope especially in destructive area of the Wenchuan earthquake which caused numerous casualties and serious economic loss. To reveal failure mechanism of bedding rock slope, this paper studied the seismic response and investigated progressive failure characteristics of the bedding rock slope through a large-scale shaking table test. A bedding rock slope of 45° contained an unfilled joint set with spacing of 0.1 m that dipped at an angle of 34° out of the surface, was conducted in a rigid model box, with a length of 3.47 m, width of 0.68 m, and height of 1.2 m, respectively. A series of tests results show that acceleration amplification factor in horizontal direction (AAF-X) increases with the increase of the slope elevation and acceleration amplification factor in vertical direction (AAF-Z) amplifies at lower part of the slope. When the shaking intensities are over 0.2 g, the slope crest and its vicinity start to show nonlinear dynamic response. Existence of bedding planes let the isoline morphology of AAF-X redistribute and dominate the seismic amplification at the crest. The progressive failure progress of the model under earthquake can be divided into four stages. This novel experiment offers some important insights to mechanism of bedding plane landslides triggered by earthquakes, evaluation stability of slopes under earthquake, and disaster prevention and mitigation.

ACS Style

Jianxian He; Shengwen Qi; Zhifa Zhan; Songfeng Guo; Chunlei Li; Bowen Zheng; Xiaolin Huang; Yu Zou; Guoxiang Yang; Ning Liang. Seismic response characteristics and deformation evolution of the bedding rock slope using a large-scale shaking table. Landslides 2021, 18, 2835 -2853.

AMA Style

Jianxian He, Shengwen Qi, Zhifa Zhan, Songfeng Guo, Chunlei Li, Bowen Zheng, Xiaolin Huang, Yu Zou, Guoxiang Yang, Ning Liang. Seismic response characteristics and deformation evolution of the bedding rock slope using a large-scale shaking table. Landslides. 2021; 18 (8):2835-2853.

Chicago/Turabian Style

Jianxian He; Shengwen Qi; Zhifa Zhan; Songfeng Guo; Chunlei Li; Bowen Zheng; Xiaolin Huang; Yu Zou; Guoxiang Yang; Ning Liang. 2021. "Seismic response characteristics and deformation evolution of the bedding rock slope using a large-scale shaking table." Landslides 18, no. 8: 2835-2853.

Original paper
Published: 08 January 2021 in Bulletin of Engineering Geology and the Environment
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The fractal geometry method has been employed to quantitatively characterize the roughness of a rock discontinuity, which is one of the key factors affecting its shear strength and the seepage characteristics of a rock mass. However, the current fractal methods involving the three-dimensional discontinuity morphology suffer from one or more problems, such as a complicated calculation procedure, an inaccurate calculation result and an inability to characterize the undulation and anisotropy of a discontinuity. To cope with these problems, the discontinuities in artificial granite samples with irregular and undulating surfaces were taken as examples, and a quantitative study on the discontinuity morphology was conducted based on the method of three-dimensional laser scanning in combination with ArcGIS data processing, geographical research, theoretical calculations and regression analysis. After performing systematic research, we proposed an extensive 3D fractal dimension including three discontinuity morphological parameters, i.e. the fractal dimension of discontinuity morphology, the ratio between the maximal undulating amplitude and the discontinuity length, and the average value of all the apparent dip angles of the discontinuity surfaces dipping opposite the shear direction. The extensive 3D fractal dimension can comprehensively characterize the roughness, undulation and anisotropy of the discontinuity morphology. A set of theoretical calculation methods were then developed to determine the three discontinuity morphological parameters of the extensive 3D fractal dimension based on ArcGIS. We finally established a mathematical expression of the extensive 3D fractal dimension. Compared with the current fractal methods, the extensive 3D fractal dimension can effectively compensate for the inability to characterize the undulation and anisotropy of the discontinuity morphology. Its calculation methods have the advantages of simplification, low-time consumption and high precision.

ACS Style

Bowen Zheng; Shengwen Qi; Guangming Luo; Fangcui Liu; Xiaolin Huang; Songfeng Guo. Characterization of discontinuity surface morphology based on 3D fractal dimension by integrating laser scanning with ArcGIS. Bulletin of Engineering Geology and the Environment 2021, 80, 2261 -2281.

AMA Style

Bowen Zheng, Shengwen Qi, Guangming Luo, Fangcui Liu, Xiaolin Huang, Songfeng Guo. Characterization of discontinuity surface morphology based on 3D fractal dimension by integrating laser scanning with ArcGIS. Bulletin of Engineering Geology and the Environment. 2021; 80 (3):2261-2281.

Chicago/Turabian Style

Bowen Zheng; Shengwen Qi; Guangming Luo; Fangcui Liu; Xiaolin Huang; Songfeng Guo. 2021. "Characterization of discontinuity surface morphology based on 3D fractal dimension by integrating laser scanning with ArcGIS." Bulletin of Engineering Geology and the Environment 80, no. 3: 2261-2281.

Journal article
Published: 06 December 2020 in Engineering Geology
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Laboratory tests revealed that by enhancing the weathering degree, a transition of pre-peak mechanical responses of crystalline rocks under unconfined compression from approximate linearity to nonlinearity was evident, as was the weakening of macro-mechanical properties. However, thus far, very few numerical studies have been conducted to quantitatively characterize the strong-to-weak transition of the mechanical behaviors of crystalline rocks modulated by the weathering degree. We propose an advanced grain-based model (AGBM) using Universal Distinct Element Code (UDEC) to characterize mechanical characteristics of crystalline rocks with different weathering degrees. The weathering-induced deterioration of microstructures was treated as loosening of grain contacts and weakening of their properties. It was proved that the grain contact model that considered hardening nonlinear deformation in compression and linearly elastic deformation in tension or shear was feasible and applicable to characterize the mechanical behaviors of crystalline rocks with different weathering degrees. The compression hardening deformation of grain contacts significantly affected the macro nonlinear stress-strain relation and stress thresholds of crack closure, crack imitation, stable crack growth, and unstable crack growth. We acquired new insights on the weathering-induced weakening of macro-mechanical characteristics of crystalline rock, which resulted from weakening of deformation properties of the grain contact more than grain contact strength.

ACS Style

Xiaolin Huang; Shengwen Qi; Bowen Zheng; Ning Liang; Lihui Li; Lei Xue; Songfeng Guo; Xiang Sun; Daping Tai. An advanced grain-based model to characterize mechanical behaviors of crystalline rocks with different weathering degrees. Engineering Geology 2020, 280, 105951 .

AMA Style

Xiaolin Huang, Shengwen Qi, Bowen Zheng, Ning Liang, Lihui Li, Lei Xue, Songfeng Guo, Xiang Sun, Daping Tai. An advanced grain-based model to characterize mechanical behaviors of crystalline rocks with different weathering degrees. Engineering Geology. 2020; 280 ():105951.

Chicago/Turabian Style

Xiaolin Huang; Shengwen Qi; Bowen Zheng; Ning Liang; Lihui Li; Lei Xue; Songfeng Guo; Xiang Sun; Daping Tai. 2020. "An advanced grain-based model to characterize mechanical behaviors of crystalline rocks with different weathering degrees." Engineering Geology 280, no. : 105951.

Journal article
Published: 12 November 2020 in Materials
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Characterization of the tensile mechanical behaviors of rocks under dynamic loads is of great significance for the practical engineering. However, thus far, its micromechanics have rarely been studied. This paper micromechanically investigated the compression-induced tensile mechanical behaviors of the crystalline rock using the grain-based model (GBM) by universal distinct element code (UDEC). Results showed that the crystalline rock has the rate- and heterogeneity-dependency of tensile behaviors. Essentially, dynamic Brazilian tensile strength increased in a linear manner as the loading rate increased. With the size distribution and morphology of grain-scale heterogeneity weakened, it increased, and this trend was obviously enhanced as the loading rate increased. Additionally, the rate-dependent characteristic became strong with the grain heterogeneity weakened. The grain heterogeneity prominently affected the stress distribution inside the synthetic crystalline rock, especially in the mixed compression and tension zone. Due to heterogeneity, there were tensile stress concentrations (TSCs) in the sample which could favor microcracking and strength weakening of the sample. As the grain heterogeneity weakened or the loading rate increased, the magnitude of the TSC had a decreasing trend and there was a transition from the sharp TSC to the smooth tensile stress distribution zone. The progressive failure of the crystalline rock was notably influenced by the loading rate, which mainly represented the formation of the crushing zone adjacent to two loading points. Our results are meaningful for the practical engineering such as underground protection works from stress waves.

ACS Style

Bowen Zheng; Shengwen Qi; Xiaolin Huang; Ning Liang; Songfeng Guo. Compression-Induced Tensile Mechanical Behaviors of the Crystalline Rock under Dynamic Loads. Materials 2020, 13, 5107 .

AMA Style

Bowen Zheng, Shengwen Qi, Xiaolin Huang, Ning Liang, Songfeng Guo. Compression-Induced Tensile Mechanical Behaviors of the Crystalline Rock under Dynamic Loads. Materials. 2020; 13 (22):5107.

Chicago/Turabian Style

Bowen Zheng; Shengwen Qi; Xiaolin Huang; Ning Liang; Songfeng Guo. 2020. "Compression-Induced Tensile Mechanical Behaviors of the Crystalline Rock under Dynamic Loads." Materials 13, no. 22: 5107.

Journal article
Published: 22 October 2020 in Materials
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The shear strength characteristics of rock masses containing non-persistent discontinuities are strongly affected by discontinuities and rock bridges. The linear Jennings criterion cannot reflect the nonlinear mechanical behavior during progressive failure of rock masses with non-persistent discontinuities. In this study, a new nonlinear shear strength criterion was developed. First of all, a series of shear test data about artificial rock mass samples were collected on the basis of the published literatures, and five types of samples were differentiated according to the positions of discontinuities. After that, a new nonlinear shear strength criterion was proposed by introducing two correction coefficients A and B into the basic form of the Jennings criterion, which could correct the weight of the cohesion and the internal friction coefficient of rock bridges respectively. Then, the new criterion was determined by fitting the basic form of the Jennings criterion with the laboratory data. It was found that the parameters A and B had a nonlinear exponential and negative exponential relation with the connectivity rate respectively. It indicated that both the cohesion and the internal friction coefficient estimated by the new criterion were superior to those estimated by the Jennings criterion. Compared with the linear Jennings criterion, the new nonlinear shear strength criterion had a better applicability.

ACS Style

Bowen Zheng; Shengwen Qi; Songfeng Guo; Xiaolin Huang; Ning Liang; Yu Zou; Guangming Luo. A New Shear Strength Criterion for Rock Masses with Non-Persistent Discontinuities Considering the Nonlinear Progressive Failure Process. Materials 2020, 13, 4694 .

AMA Style

Bowen Zheng, Shengwen Qi, Songfeng Guo, Xiaolin Huang, Ning Liang, Yu Zou, Guangming Luo. A New Shear Strength Criterion for Rock Masses with Non-Persistent Discontinuities Considering the Nonlinear Progressive Failure Process. Materials. 2020; 13 (21):4694.

Chicago/Turabian Style

Bowen Zheng; Shengwen Qi; Songfeng Guo; Xiaolin Huang; Ning Liang; Yu Zou; Guangming Luo. 2020. "A New Shear Strength Criterion for Rock Masses with Non-Persistent Discontinuities Considering the Nonlinear Progressive Failure Process." Materials 13, no. 21: 4694.

Article
Published: 01 October 2020 in Journal of Central South University
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The rock mass in nature is in most cases anisotropic, while the existing classifications are mostly developed with the assumption of isotropic conditions that not always meet the engineering requirements. In this study, an anisotropic system based on China National Standard of BQ, named as A-BQ, is developed to address the classification of anisotropic rock mass incorporating the anisotropy degree as well as the quality of rock mass. Two series of basic rating factors are incorporated including inherent anisotropy and structure anisotropy. The anisotropy degree of rock mass is characterized by the ratio of maximum to minimum quality score and adjusted by the confining stress. The quality score of rock mass is determined by the key factors of anisotropic structure occurrence and the correction factors of stress state and groundwater condition. The quality of rock mass is characterized by a quality score and classified in five grades. The assessment of stability status and probable failure modes are also suggested for tunnel and slope engineering for different quality grades. Finally, two cases of tunnel and slope are presented to illustrate the application of the developed classification system into the rock masses under varied stress state.

ACS Style

Song-Feng Guo; Sheng-Wen Qi; Charalampos Saroglou. A-BQ, a classification system for anisotropic rock mass based on China National Standard. Journal of Central South University 2020, 27, 3090 -3102.

AMA Style

Song-Feng Guo, Sheng-Wen Qi, Charalampos Saroglou. A-BQ, a classification system for anisotropic rock mass based on China National Standard. Journal of Central South University. 2020; 27 (10):3090-3102.

Chicago/Turabian Style

Song-Feng Guo; Sheng-Wen Qi; Charalampos Saroglou. 2020. "A-BQ, a classification system for anisotropic rock mass based on China National Standard." Journal of Central South University 27, no. 10: 3090-3102.

Original paper
Published: 29 September 2020 in Natural Hazards
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Empirical methods are commonly employed to predict the PGA distribution of an earthquake and are widely used. However, current empirical methods assume the seismic source to be a point source, a line source, or a plane source, where the energy is concentrated and released uniformly. An empirical attenuation model of the near-field peak ground acceleration (PGA) was proposed that considers a nonuniform spatial distribution of seismic fault energy and its 3D scale. Then, this model was used to reconstruct the PGA distribution of the 2008 Wenchuan, China, Mw7.9 earthquake based on the data of a seismic fault model and ground acceleration records of the mainshock and aftershocks collected by seismic stations. The predicted PGA values show similar attenuation characteristics to the interpolated map of the PGA recorded by seismic stations. A comparison with the results of a finite-fault model developed by the USGS indicates that the proposed model can provide more details and give a more precise result in the near field. The analysis of landslides triggered by the Wenchuan earthquake demonstrates that the PGA distribution estimated by this model can be used to validate the findings of other researchers.

ACS Style

Xianglong Yao; Shengwen Qi; Chunling Liu; Songfeng Guo; Xiaoling Huang; Chong Xu; Bowen Zheng; Zhifa Zhan; Yu Zou. An empirical attenuation model of the peak ground acceleration (PGA) in the near field of a strong earthquake. Natural Hazards 2020, 105, 691 -715.

AMA Style

Xianglong Yao, Shengwen Qi, Chunling Liu, Songfeng Guo, Xiaoling Huang, Chong Xu, Bowen Zheng, Zhifa Zhan, Yu Zou. An empirical attenuation model of the peak ground acceleration (PGA) in the near field of a strong earthquake. Natural Hazards. 2020; 105 (1):691-715.

Chicago/Turabian Style

Xianglong Yao; Shengwen Qi; Chunling Liu; Songfeng Guo; Xiaoling Huang; Chong Xu; Bowen Zheng; Zhifa Zhan; Yu Zou. 2020. "An empirical attenuation model of the peak ground acceleration (PGA) in the near field of a strong earthquake." Natural Hazards 105, no. 1: 691-715.

Journal article
Published: 06 September 2020 in Materials
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This paper microscopically investigated progressive failure characteristics of brittle rock under high-strain-rate compression using the bonded particle model (BPM). We considered the intact sample and the flawed sample loaded by split Hopkinson pressure bar respectively. Results showed that the progressive failure characteristics of the brittle rock highly depended on the strain rate. The intact sample first experienced in microcracking, then crack coalescing, and finally splitting into fragments. The total number of the micro cracks, the proportion of the shear cracks, the number of fragments and the strain at the peak stress all increased with the increasing strain rate. Also, a transition existed for the failure of the brittle rock from brittleness to ductility as the strain rate increased. For the flawed sample, the microcracking initiation position and the types of the formed macro cracks were influenced by the flaw angle in the initial stage. However, propagation of these early-formed macro cracks were prohibited in the later stages. New micro cracks were produced and then coalesced into diagonal macro cracks which could all form ‘X’-shape failure configuration regardless of the incline angle of the flaw. We explored micromechanics on progressive failure characteristics of the brittle rock under dynamic loads.

ACS Style

Xiaolin Huang; Shengwen Qi; Bowen Zheng; Songfeng Guo; Ning Liang; Zhifa Zhan. Progressive Failure Characteristics of Brittle Rock under High-Strain-Rate Compression Using the Bonded Particle Model. Materials 2020, 13, 3943 .

AMA Style

Xiaolin Huang, Shengwen Qi, Bowen Zheng, Songfeng Guo, Ning Liang, Zhifa Zhan. Progressive Failure Characteristics of Brittle Rock under High-Strain-Rate Compression Using the Bonded Particle Model. Materials. 2020; 13 (18):3943.

Chicago/Turabian Style

Xiaolin Huang; Shengwen Qi; Bowen Zheng; Songfeng Guo; Ning Liang; Zhifa Zhan. 2020. "Progressive Failure Characteristics of Brittle Rock under High-Strain-Rate Compression Using the Bonded Particle Model." Materials 13, no. 18: 3943.

Journal article
Published: 18 August 2020 in Engineering Geology
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There are an increasing number of mega engineering projects of removing the top of hills to fill in the valley for new land creation in the Loess Plateau of China, which significantly changes the hydrological and geological equilibrium state of the site. The formation of a new hydrological equilibrium state is associated with the water movement in the compacted and intact loess layers. Most disasters occurring in the loess area are related to water. The soil-water retention curve (SWRC) is the key to the implementation of unsaturated soil mechanics in engineering practice and is required to numerically model the movement of water in the soil. In this study, the SWRCs and microstructure of intact and compacted specimens from Lanzhou and Yan'an, two typical cities that have new land creation projects, are investigated. The SWRC is obtained using the filter paper method. The mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) techniques are used to explore the microstructure. The results highlight that the intact loess has a higher air occlusion value (AOV) and a similar slope of SWRC in the transition zone compared with the remolded specimens that compacted at the natural water content. The normalized SWRC (i.e., degree of saturation versus suction/AVO) of the intact specimen is approximately the same as the remolded specimens compacted as the natural water content. The difference in the microstructure between intact and compacted specimens originates from different existing states of the clay particles and further contributes to the variation of the SWRC.

ACS Style

Xiaokun Hou; Shengwen Qi; Tonglu Li; Songfeng Guo; Yu Wang; Yan Li; Linxin Zhang. Microstructure and soil-water retention behavior of compacted and intact silt loess. Engineering Geology 2020, 277, 105814 .

AMA Style

Xiaokun Hou, Shengwen Qi, Tonglu Li, Songfeng Guo, Yu Wang, Yan Li, Linxin Zhang. Microstructure and soil-water retention behavior of compacted and intact silt loess. Engineering Geology. 2020; 277 ():105814.

Chicago/Turabian Style

Xiaokun Hou; Shengwen Qi; Tonglu Li; Songfeng Guo; Yu Wang; Yan Li; Linxin Zhang. 2020. "Microstructure and soil-water retention behavior of compacted and intact silt loess." Engineering Geology 277, no. : 105814.

Journal article
Published: 13 July 2020 in Applied Sciences
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A rock mass often contains joints filled with a viscoelastic medium of which seismic response is significant to geophysical exploration and seismic engineering design. Using the propagator matrix method, an analytical model was established to characterize the seismic response of viscoelastic filled joints. Stress wave propagation through a single joint highly depended on the water content and thickness of the filling as well as the frequency and incident angle of the incident wave. The increase in the water content enhanced the viscosity (depicted by quality factor) of the filled joint, which could promote equivalent joint stiffness and energy dissipation with double effects on stress wave propagation. There existed multiple reflections when the stress wave propagated through a set of filled joints. The dimensionless joint spacing was the main controlling factor in the seismic response of the multiple filled joints. As it increased, the transmission coefficient first increased, then it decreased instead, and at last it basically kept invariant. The effect of multiple reflections was weakened by increasing the water content, which further influenced the variation of the transmission coefficient. The water content of the joint filling should be paid more attention in practical applications.

ACS Style

Xiaolin Huang; Shengwen Qi; Bowen Zheng; Youshan Liu; Lei Xue; Ning Liang. Stress Wave Propagation through Rock Joints Filled with Viscoelastic Medium Considering Different Water Contents. Applied Sciences 2020, 10, 4797 .

AMA Style

Xiaolin Huang, Shengwen Qi, Bowen Zheng, Youshan Liu, Lei Xue, Ning Liang. Stress Wave Propagation through Rock Joints Filled with Viscoelastic Medium Considering Different Water Contents. Applied Sciences. 2020; 10 (14):4797.

Chicago/Turabian Style

Xiaolin Huang; Shengwen Qi; Bowen Zheng; Youshan Liu; Lei Xue; Ning Liang. 2020. "Stress Wave Propagation through Rock Joints Filled with Viscoelastic Medium Considering Different Water Contents." Applied Sciences 10, no. 14: 4797.

Journal article
Published: 08 July 2020 in Sustainability
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A gigantic project named Gully Land Consolidation (GLC) was launched in the hill-gully region of the Chinese Loess Plateau in 2011 to cope with land degradation and create new farmlands for cultivation. However, as a particular kind of remolded loess, the newly created and backfilled farmland may bring new engineering and environmental problems because the soil structure was disturbed and destroyed. In this study, current situations and characteristics of GLC are introduced. Test results show that physical-mechanical properties and microstructural characteristics of backfilled loess of one-year and five-year farmland are significantly affected by the Gully Land Consolidation project. Compared to natural loess, the moisture content, density, and internal friction angle of backfilled loess increase. On the contrary, the porosity, plasticity index, particle size index, and cohesion index decrease. Through SEM tests, it is observed that the particles of backfilled loess are rounded, with large pores filled with crushed fine particles, which results in skeleton strength weakness among particles and pores. The pore size distribution (PSD) of the four types of loess (Q3 loess, Q2 loess, one-year farmland, and five-year farmland) was measured using mercury intrusion porosimetry (MIP) tests, showing that the pore size of Q3 loess is mainly mesopores 4000–20,000 nm in size, accounting for 67.5%. The Q2, five-year, and one-year farmland loess have mainly small pores 100–4000 nm in size, accounting for 52.5%, 51.7%, and 71.7%, respectively. The microscopic analysis shows that backfill action degrades the macropores and mesopores into small pores and micropores, leading to weak connection strength among soil particles, which further affects the physical-mechanical properties of loess. The disturbance of backfilled loess leads to an obvious decrease in cohesion and a slight increase in internal friction compared to natural loess. The farming effect becomes prominent with increased backfill time, while the loess soil moisture content increases gradually. Both the cohesion and internal friction of the backfilled loess soil decrease to different degrees. This study is helpful to investigate sustainable land use in the Chinese Loess Plateau and similar areas.

ACS Style

Lina Ma; Shengwen Qi; Bowen Zheng; Songfeng Guo; Qiangbing Huang; Xinbao Yu. Farming Influence on Physical-Mechanical Properties and Microstructural Characteristics of Backfilled Loess Farmland in Yan’an, China. Sustainability 2020, 12, 5516 .

AMA Style

Lina Ma, Shengwen Qi, Bowen Zheng, Songfeng Guo, Qiangbing Huang, Xinbao Yu. Farming Influence on Physical-Mechanical Properties and Microstructural Characteristics of Backfilled Loess Farmland in Yan’an, China. Sustainability. 2020; 12 (14):5516.

Chicago/Turabian Style

Lina Ma; Shengwen Qi; Bowen Zheng; Songfeng Guo; Qiangbing Huang; Xinbao Yu. 2020. "Farming Influence on Physical-Mechanical Properties and Microstructural Characteristics of Backfilled Loess Farmland in Yan’an, China." Sustainability 12, no. 14: 5516.

Technical note
Published: 01 July 2020 in Rock Mechanics and Rock Engineering
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Barla G, Barla M, Martinotti ME (2010) Development of a new direct shear testing apparatus. Rock Mech Rock Eng 43(1):117–122 Google Scholar Barton N (1973) Review of a new shear-strength criterion for rock joints. Eng Geol 7(4):287–332 Google Scholar Barton N, Choubey V (1977) The shear strength of rock joints in theory and practice. Rock Mech 10(1):1–54 Google Scholar Cen DF, Huang D (2017) Direct shear tests of sandstone under constant normal tensile stress condition using a simple auxiliary device. Rock Mech Rock Eng 50:1425–1438 Google Scholar Crawford AM, Curran JH (1981) The influence of shear velocity on the frictional resistance of rock discontinuities. Int J Rock Mech Min Sci Geomech Abstr Pergamon 18(6):505–515 Google Scholar Dang WG, Konietzky H, Frühwirt T (2016) Direct shear behavior of a plane joint under dynamic normal load (DNL) conditions. Eng Geol 213:133–141 Google Scholar Fathi A, Moradian Z, Rivard P et al (2016) Shear mechanism of rock joints under pre-peak cyclic loading condition. Int J Rock Mech Min Sci 83:197–210 Google Scholar Grasselli G, Egger P (2003) Constitutive law for the shear strength of rock joints based on three-dimensional surface parameters. Int J Rock Mech Min Sci 40(1):25–40 Google Scholar Guo SF, Qi SW (2015) Numerical study on progressive failure of hard rock samples with an unfilled undulate joint. Eng Geol 193:173–182 Google Scholar Hans J, Boulon M (2003) A new device for investigating the hydro-mechanical properties of rock joints. Int J Numer Anal Methods Geomech 27(6):513–548 Google Scholar Hu YX, Liu SC, Dong W (1996) Earthquake engineering. CRC Press, London Google Scholar Huang D, Zhu TT (2018) Experimental and numerical study on the strength and hybrid fracture of sandstone under tension-shear stress. Eng Fract Mech 200:387–400 Google Scholar Huang D, Zhu TT (2019) Experimental study on the shear mechanical behavior of sandstone under normal tensile stress using a new double-shear testing device. Rock Mech Rock Eng 52(9):3467–3474 Google Scholar Indraratna B, Haque A, Aziz N (1998) Laboratory modelling of shear behaviour of soft joints under constant normal stiffness conditions. Geotech Geol Eng 16(1):17–44 Google Scholar ISRM (2007) The complete ISRM suggested methods for rock characterization, testing and monitoring: 1974–2006. In: Ulusay R, Hudson JA (eds) Suggested methods prepared by the commission on testing methods, international society for rock mechanics, compilation arranged by the ISRM Turkish national group. Kozan Ofset, Ankara Google Scholar Jiang Y, Xiao J, Tanabashi Y et al (2004) Development of an automated servo-controlled direct shear apparatus applying a constant normal stiffness condition. Int J Rock Mech Min Sci 41(2):275–286 Google Scholar Kleepmek M, Khamrat S, Thongprapha T et al (2016) Displacement velocity effects on rock fracture shear strengths. J Struct Geol 90:48–60 Google Scholar Konietzky H, Frühwirt T, Luge H (2012) A new large dynamic rockmechanical direct shear box device. Rock Mech Rock Eng 45(3):427–432 Google Scholar Li HB, Feng HP, Liu B et al (2006) Experimental studies on mechanical properties of rock joints under dynamic loading. Key Eng Mater 326–328:1709–1712 Google Scholar Li JC, Ma GW, Zhao J (2011) Analysis of stochastic seismic wave interaction with a slippery rock fault. Rock Mech Rock Eng 44(1):85–92 Google Scholar Li JC, Li HB, Jiao YY, Liu YQ, Xia X, Yu C (2014) Analysis for oblique wave propagation across filled joints based on thin-layer interface model. J Appl Geophys 102:39–46 Google Scholar Mehrishal S, Sharifzadeh M, Shahriar K et al (2016) An experimental study on normal stress and shear rate dependency of basic friction coefficient in dry and wet limestone joints. Rock Mech Rock Eng 49(12):4607–4629 Google Scholar Patton FD (1966) Multiple modes of shear failure in rock. In; Proceedings of the 1st Congress of International Society for Rock Mechanics, Lisbon, Portugal, 25 September–1 October. pp. 509–513 Qi SW, Xu Q, Lan HX et al (2010) Spatial distribution analysis of landslides triggered by 2008.5.12 Wenchuan earthquake. China Eng Geol 116:95–108 Google Scholar Qi SW, Xu Q, Zhang B et al (2011) Source characteristics of long runout rock avalanches triggered by the 2008 Wenchuan earthquake, China. J Asian Earth Sci 40:896–906 Google Scholar Qi SW, Lan HX, Dong JY (2015) An analytical solution to slip buckling slope failure triggered by earthquake. Eng Geol 194:4–11 Google Scholar Schneider HJ (1977) The time dependence of friction of rock joints. Bull Int Assoc Eng Geol 16:235–239 Google Scholar Zheng BW, Qi SW (2016) A new index to describe joint roughness coefficient (JRC) under cyclic shear. Eng Geol 212:72–85 Google Scholar Zhu TT, Huang D (2019) Experimental investigation of the shear mechanical behavior of sandstone under unloading normal stress. Int J Rock Mech Min Sci 114:186–194 Google Scholar Download references We want to remember Prof. Barla, who unexpectedly passed away. This paper was encouraged positively and revised meticulously by Prof. Barla in the process of its submission. Unfortunately, during the modification of the manuscript after review, the grievous news of Prof. Barla came suddenly and we are all in extreme grief. This article is dedicated to distinguished Prof. Barla to cherish our memory for him. This research was supported with funds from the National Natural Science Foundation of China under Grant Nos. 41825018, 41672307 and the Chinese Academy of Sciences under Knowledge Innovation Project Grant No. KZZD-EW-05-02. Key Laboratory of Shale Gas and Geoengineering, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China Shengwen Qi, Bowen Zheng, Xiaolin Huang, Songfeng Guo & Yu Zou Innovation Academy for Earth Science, Chinese...

ACS Style

Shengwen Qi; Bowen Zheng; Faquan Wu; Xiaolin Huang; Songfeng Guo; Zhifa Zhan; Yu Zou; Giovanni Barla. A New Dynamic Direct Shear Testing Device on Rock Joints. Rock Mechanics and Rock Engineering 2020, 53, 4787 -4798.

AMA Style

Shengwen Qi, Bowen Zheng, Faquan Wu, Xiaolin Huang, Songfeng Guo, Zhifa Zhan, Yu Zou, Giovanni Barla. A New Dynamic Direct Shear Testing Device on Rock Joints. Rock Mechanics and Rock Engineering. 2020; 53 (10):4787-4798.

Chicago/Turabian Style

Shengwen Qi; Bowen Zheng; Faquan Wu; Xiaolin Huang; Songfeng Guo; Zhifa Zhan; Yu Zou; Giovanni Barla. 2020. "A New Dynamic Direct Shear Testing Device on Rock Joints." Rock Mechanics and Rock Engineering 53, no. 10: 4787-4798.

Journal article
Published: 19 June 2020 in Engineering Geology
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A large number of traffic systems in China pass through a large area of frozen soil, most of which contains frozen soil–rock mixtures (FSRMs). For a profound understanding of the mechanical behaviours and damage mechanisms of geotechnical and geoenvironmental projects, it is necessary to understand the stress–strain characteristics and failure modes of FSRMs. This study focuses on the uniaxial compression strength (UCS), Young's modulus, and complete stress–strain curve under loading, considering the post-peak behaviour. More than 250 FSRM specimens were tested for UCS evaluations, while considering the effects of different freezing temperatures (−5, −10, −20, −30, and − 40 °C), initial water contents (15.0, 25.0, and 30.0%), and volumetric block proportions (0, 30, 40, 50, and 100%). The stress–strain curve of the FSRM was characterised by six distinct stress levels and deformation stages, different from those of rock or soil in the normal state. Particularly, the turning point from volume compression to expansion was observed after the post-peak, at which superficial cracks were initiated. Ice crystals provided ductility of the FSRM and maximised its load capacity to prevent premature cracks on the FSRM surface. The block stone hindered the linear propagation of cracks. The failure patterns of the FSRM for the UCS evaluation could be classified into four types. The UCS was influenced by mainly the strength of the mixture composed of ice crystals and soil particles and friction and occlusal strength between blocks. Notably, the gradual thawing of the FSRM might cause the largest deformation at the bottom of the active layer in summer and autumn, according to the experimental results. Thus, it is very important to understand the strength characteristics, deformation stages, and failure patterns associated with the geomechanical behaviour of the FSRM for engineering design and applications in a permafrost region.

ACS Style

Zhiqing Li; Feng Hu; Shengwen Qi; Ruilin Hu. Strain-softening failure mode after the post-peak as a unique mechanism of ruptures in a frozen soil-rock mixture. Engineering Geology 2020, 274, 105725 .

AMA Style

Zhiqing Li, Feng Hu, Shengwen Qi, Ruilin Hu. Strain-softening failure mode after the post-peak as a unique mechanism of ruptures in a frozen soil-rock mixture. Engineering Geology. 2020; 274 ():105725.

Chicago/Turabian Style

Zhiqing Li; Feng Hu; Shengwen Qi; Ruilin Hu. 2020. "Strain-softening failure mode after the post-peak as a unique mechanism of ruptures in a frozen soil-rock mixture." Engineering Geology 274, no. : 105725.

Journal article
Published: 14 June 2020 in Applied Sciences
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The shear strength of the rock discontinuities under different shear rates is of great importance to evaluate the stability of rock mass engineering, which is remarkably influenced by the size effects induced by both the length and the undulated amplitude of discontinuities. An advanced shear strength criterion taking into account the size and the shear rate simultaneously was proposed. There is an advantage of the dimension unity in terms of the new shear strength criterion in comparison to previous related empirical equations. Additionally, it can be degraded into the International Society for Rock Mechanics (ISRM)-suggested Barton shear strength empirical equation on the peak shear strength of the rock discontinuities. Then, based on a new dynamic direct shear testing device on rock joints, the granite discontinuities with various lengths (200 mm to 1000 mm) and undulated amplitudes (3 mm to 23 mm) were designed to conduct direct shear tests under different low shear rates (0 mm/s to 1 mm/s) to verify the involved empirical equations. It was found that the results predicted by the new shear strength criterion agreed well with the experimental results. It was proved that the new shear strength criterion had a better applicability to characterize the shear strength of the rock discontinuities.

ACS Style

Bowen Zheng; Shengwen Qi; Xiaolin Huang; Songfeng Guo; Chonglang Wang; Zhifa Zhan; Guangming Luo. An Advanced Shear Strength Criterion for Rock Discontinuities Considering Size and Low Shear Rate. Applied Sciences 2020, 10, 1 .

AMA Style

Bowen Zheng, Shengwen Qi, Xiaolin Huang, Songfeng Guo, Chonglang Wang, Zhifa Zhan, Guangming Luo. An Advanced Shear Strength Criterion for Rock Discontinuities Considering Size and Low Shear Rate. Applied Sciences. 2020; 10 (12):1.

Chicago/Turabian Style

Bowen Zheng; Shengwen Qi; Xiaolin Huang; Songfeng Guo; Chonglang Wang; Zhifa Zhan; Guangming Luo. 2020. "An Advanced Shear Strength Criterion for Rock Discontinuities Considering Size and Low Shear Rate." Applied Sciences 10, no. 12: 1.

Journal article
Published: 22 May 2020 in Scientific Reports
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The pore structure is one of the most important properties of soil, which can directly affect the other properties such as water content, permeability and strength. It is of great significance to study the soil pore structure for agricultural cultivation, water and soil conservation and engineering construction. This paper investigates the 3D pore characterization of intact loess and four kinds of compacted loess (with different dry density) in northwest China. Micro scale computed tomography and mercury intrusion porosimetry tests were performed to get the porosity, specific surface area, pore size distribution, connected pores content and isolated pores content of different samples. Results show that the intact loess has more connected pores than the compacted loess, and the compacted loess whose dry density appears to be modelled well still have different pore structure with the intact loess. In addition, as the compactness increasing, the large pores (>13 μm) were firstly broken into medium pores (8~13 μm) and some small pores (<8 μm) until the pore structure was close to the natural structure of the intact loess, after that medium pores began to be broken into small pores.

ACS Style

Linxin Zhang; Shengwen Qi; Lina Ma; Songfeng Guo; Zhiqing Li; Guoliang Li; Jijin Yang; Yu Zou; Tonglu Li; Xiaokun Hou. Three-dimensional pore characterization of intact loess and compacted loess with micron scale computed tomography and mercury intrusion porosimetry. Scientific Reports 2020, 10, 1 -15.

AMA Style

Linxin Zhang, Shengwen Qi, Lina Ma, Songfeng Guo, Zhiqing Li, Guoliang Li, Jijin Yang, Yu Zou, Tonglu Li, Xiaokun Hou. Three-dimensional pore characterization of intact loess and compacted loess with micron scale computed tomography and mercury intrusion porosimetry. Scientific Reports. 2020; 10 (1):1-15.

Chicago/Turabian Style

Linxin Zhang; Shengwen Qi; Lina Ma; Songfeng Guo; Zhiqing Li; Guoliang Li; Jijin Yang; Yu Zou; Tonglu Li; Xiaokun Hou. 2020. "Three-dimensional pore characterization of intact loess and compacted loess with micron scale computed tomography and mercury intrusion porosimetry." Scientific Reports 10, no. 1: 1-15.

Editorial
Published: 20 April 2020 in Engineering Geology
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Shengwen Qi; Renato Macciotta; Keh-Jian Shou; Charalampos Saroglou. Preface to the Special Issue on “Advances in Rock Mass Engineering Geomechanics”. Engineering Geology 2020, 272, 105642 .

AMA Style

Shengwen Qi, Renato Macciotta, Keh-Jian Shou, Charalampos Saroglou. Preface to the Special Issue on “Advances in Rock Mass Engineering Geomechanics”. Engineering Geology. 2020; 272 ():105642.

Chicago/Turabian Style

Shengwen Qi; Renato Macciotta; Keh-Jian Shou; Charalampos Saroglou. 2020. "Preface to the Special Issue on “Advances in Rock Mass Engineering Geomechanics”." Engineering Geology 272, no. : 105642.

Journal article
Published: 27 February 2020 in Engineering Geology
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The failure of geomaterials has been well recognized as a process of crack evolution due to heterogeneity. However, the influence of confining stresses on the progressive failure process has still not been fully understood. In this study, a series of numerical simulations were conducted to study the confinement effects after being calibrated by the existing experimental observations. A Gaussian distribution function and a plastic strain-dependent strength model were adopted to depict the heterogeneity and the variable mechanical parameters of the materials, respectively. The results reveal that the tensile cracks are dominant for experiments under low confining stresses, while shear cracks become more dominant as the confinement increases. The total acoustic emission (AE) events demonstrates a “U" shape, i.e. decrease firstly, and then keep nearly invariant, subquentently increase as confining stress increases. These investigations indicate that the dominant effects of confining stress on cracking mechanisms are constraint on tensile cracks under low confining stresses and promotion for shear damages under high confining stresses. The results of AE events intensity disclose that macro failure always occurs in the post-peak domain. The confining stress can advance the macro failure occurrence from the post-failure domain towards the pre-peak stress domain, and increase the uniformity of damages occurred in materials. The fitting analysis shows that the relation of crack initiation stresses to confining stresses can be well represented by a nonlinear equation. This study can improve our understanding of the failure features of geomaterials resulting from stress state changes in engineering.

ACS Style

Songfeng Guo; Shengwen Qi; Zhifa Zhan; Lina Ma; Ephrem Getahun Gure; Shishu Zhang. Numerical study on the progressive failure of heterogeneous geomaterials under varied confining stresses. Engineering Geology 2020, 269, 105556 .

AMA Style

Songfeng Guo, Shengwen Qi, Zhifa Zhan, Lina Ma, Ephrem Getahun Gure, Shishu Zhang. Numerical study on the progressive failure of heterogeneous geomaterials under varied confining stresses. Engineering Geology. 2020; 269 ():105556.

Chicago/Turabian Style

Songfeng Guo; Shengwen Qi; Zhifa Zhan; Lina Ma; Ephrem Getahun Gure; Shishu Zhang. 2020. "Numerical study on the progressive failure of heterogeneous geomaterials under varied confining stresses." Engineering Geology 269, no. : 105556.

Journal article
Published: 22 November 2019 in Engineering Geology
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Earthquake-induced slope failure often results in a large loss of life and property, and thus, understanding how a slope responds to seismic shaking can reveal the mechanism and movement of this kind of phenomenon. After the 2008 Wenchuan earthquake, a dense array of strong earthquake seismographs were deployed along the Lengzhuguan slope, Luding County, Sichuan Province, Southwest China, to study the seismic response of the slope. Three main shocks were recorded in 2014 and 2015, with epicenter distances between 34 km and 70 km. Observation data show that the ground motion was polarized in the direction perpendicular to the elongation direction of the ridge (near 50° azimuth from North), with an amplification coefficient >10 and a ground motion amplification frequency band between 1.5 and 2.5 Hz. The results of a series of numerical simulation experiments conducted using the finite difference method indicate that the observed seismic response characteristics of the Lengzhuguan slope can be reproduced only by a heterogeneous model containing a loose deposit layer with a thickness of 30 m. It was found that geological and topographic conditions resulted in complex slope seismic response characteristics that were coupled in both time and frequency, and the geological conditions dominated the seismic response of the slope. In terms of co-seismic landslide hazard, more attention should be given to subsurface lithology and rock mass structure.

ACS Style

Jianxian He; Shengwen Qi; Yunsheng Wang; Charalampos Saroglou. Seismic response of the Lengzhuguan slope caused by topographic and geological effects. Engineering Geology 2019, 265, 105431 .

AMA Style

Jianxian He, Shengwen Qi, Yunsheng Wang, Charalampos Saroglou. Seismic response of the Lengzhuguan slope caused by topographic and geological effects. Engineering Geology. 2019; 265 ():105431.

Chicago/Turabian Style

Jianxian He; Shengwen Qi; Yunsheng Wang; Charalampos Saroglou. 2019. "Seismic response of the Lengzhuguan slope caused by topographic and geological effects." Engineering Geology 265, no. : 105431.