This page has only limited features, please log in for full access.
Researches on the energy evolution of the key blocks is helpful to reveal the failure process of locked-segment type slope, whose stability is governed by the locked segment along the potential slip surface. In order to study the failure mechanism of the locked segment in the process of slope progressive failure due to strength attenuation, a series of stability analysis on the numerical models of locked-segment type slope were implemented to record the relationship curve between energy and strength reduction coefficient. Then, according to the variation law and characteristic of energy evolution, the failure process of the locked segment was divided into four stages: elastic stage, initial damage stage, extensive damage stage and failure stage. And the reduction coefficient corresponding to the peak of the energy evolution curve was employed to achieve landslide warning. In addition, the method to determine the safety factor of locked-segment type slope was given, and its reliability was verified by comparing with other traditional methods. Finally, the formula for calculating the initial sliding velocity was presented based on the residual strain energy which is defined as the elastic strain energy of the locked segment when the slope is unstable.
Xiangjie Yin; Hang Lin; Yifan Chen; Yi Tang; Yixian Wang; Yanlin Zhao; Weixun Yong. Stability Analysis of Slope Considering the Energy Evolution of Locked Segment. Geotechnical and Geological Engineering 2021, 1 -10.
AMA StyleXiangjie Yin, Hang Lin, Yifan Chen, Yi Tang, Yixian Wang, Yanlin Zhao, Weixun Yong. Stability Analysis of Slope Considering the Energy Evolution of Locked Segment. Geotechnical and Geological Engineering. 2021; ():1-10.
Chicago/Turabian StyleXiangjie Yin; Hang Lin; Yifan Chen; Yi Tang; Yixian Wang; Yanlin Zhao; Weixun Yong. 2021. "Stability Analysis of Slope Considering the Energy Evolution of Locked Segment." Geotechnical and Geological Engineering , no. : 1-10.
The constitutive models of rock are essentially the general depictions of the mechanical responses of rock mass under complex geological environments. Statistical distribution-based constitutive models are of great efficacy in reflecting the rock failure process and the stress–strain relation from the perspective of damage, while most of which were achieved by adopting Drucker–Prager criterion or Mohr–Coulomb criterion to characterize microelement failure. In this study, underpinned by Hoek–Brown strength criterion and damage theory, a new statistical damage constitutive model, which is simple in terms of model expression and capable of reflecting the strain softening characteristics of rock in post-peak stage, was established. First, the rock in the failure process was divided into infinite microelements including elastic part satisfying Hooke’s law and damaged part retaining residual strength. Based on strain equivalence hypothesis, the relation between rock microelement strength and damage variable was derived. By assuming the statistical law of microelement strength obeying Weibull distribution and the microelement failure conforming to Hoek–Brown criterion, the new statistical damage constitutive model based on Hoek–Brown criterion was, therefore, gained. The mathematical expressions of the corresponding model parameters were subsequently deduced in accordance with the geometric characteristics of the deviatoric stress–strain curve. Last, the existing conventional triaxial compression test data of representative rock samples under different confining stresses were employed to compare with the theoretical curves by proposed model, the consistency between which was quantified by utilizing the correlation factor evaluation method. The result indicated that the proposed model could well describe the entire stress–strain relationship of rock failure process and manifest the characteristics of rock residual strength. It is of great significance to the researches on rock damage and softening issues and rock reinforcement treatments.
Yifan Chen; Hang Lin; Yixian Wang; Shijie Xie; Yanlin Zhao; Weixun Yong. Statistical damage constitutive model based on the Hoek–Brown criterion. Archives of Civil and Mechanical Engineering 2021, 21, 1 -9.
AMA StyleYifan Chen, Hang Lin, Yixian Wang, Shijie Xie, Yanlin Zhao, Weixun Yong. Statistical damage constitutive model based on the Hoek–Brown criterion. Archives of Civil and Mechanical Engineering. 2021; 21 (3):1-9.
Chicago/Turabian StyleYifan Chen; Hang Lin; Yixian Wang; Shijie Xie; Yanlin Zhao; Weixun Yong. 2021. "Statistical damage constitutive model based on the Hoek–Brown criterion." Archives of Civil and Mechanical Engineering 21, no. 3: 1-9.
The locked section is a kind of geological structure that is commonly found in natural slopes. The instability criterion of the slope with a locked section structure is not yet studied. In accordance with the mechanical properties of this type of slope, the rock mass is divided into several rock blocks along its joint distribution, and the upper limit method of plastic limit analysis is introduced. By combining the principle of virtual work and the characteristics of the slope, a virtual speed is assigned to the slope and the locked section. In addition, the maximum elastic strain energy that can be accumulated in the locked section is calculated to derive its deformation rate and internal energy dissipation power. The virtual velocity, internal energy dissipation power, and gravity work power of the locked section and the rock slope are solved simultaneously in accordance with the Mohr–Coulomb correlation flow law. Finally, the formula for calculating the safety factor of this type of slope under shear failure mode is derived. A slope in Xikou, Sichuan, China, is taken as an example to verify the proposed model.
Yi Tang; Hang Lin; Yixian Wang; Yanlin Zhao. Rock slope stability analysis considering the effect of locked section. Bulletin of Engineering Geology and the Environment 2021, 80, 7241 -7251.
AMA StyleYi Tang, Hang Lin, Yixian Wang, Yanlin Zhao. Rock slope stability analysis considering the effect of locked section. Bulletin of Engineering Geology and the Environment. 2021; 80 (9):7241-7251.
Chicago/Turabian StyleYi Tang; Hang Lin; Yixian Wang; Yanlin Zhao. 2021. "Rock slope stability analysis considering the effect of locked section." Bulletin of Engineering Geology and the Environment 80, no. 9: 7241-7251.
This paper investigates the temporal-spatial characteristics of ground displacements as well as vertical and horizontal displacements and axial forces in existing piles induced by twin shield tunneling in clays. To that end, a case study and three-dimensional (3D) finite element (FE) analysis were performed. Based on the in situ monitoring data from the presented twin tunneling case history with existing piles beneath, the adopted 3D FE method was validated to be competent to yield reasonable simulation results. The validated 3D FE method was then used to analyze the effects of the distance between the tunnel and the pile, the distance between tunnel faces, and the pile length on the horizontal and vertical displacements and axial stresses in piles. It was found that the horizontal displacement distribution forms along the pile shaft for the front piles are similar to that for the back piles, whereas the magnitudes of the horizontal displacements of the front piles are slightly larger than that of the back piles. The interactions between piles in the pile group provide protection of the middle piles in the pile group against twin tunneling effects. With a reduction in the distance between the tunnel and the pile, the pile displacements and stresses increase nonlinearly. With an increase in the distance between tunnel faces, the maximum positive pile displacements and the maximum and minimum axial pile stresses increase, while the maximum negative pile displacements and the difference between the maximum and minimum axial pile stresses decrease.
Minghong Sheng; Jingjing Gao; Panpan Guo; Rihong Cao; Yixian Wang. Temporal-Spatial Characteristics of Ground and Pile Responses to Twin Shield Tunneling in Clays. Geofluids 2021, 2021, 1 -15.
AMA StyleMinghong Sheng, Jingjing Gao, Panpan Guo, Rihong Cao, Yixian Wang. Temporal-Spatial Characteristics of Ground and Pile Responses to Twin Shield Tunneling in Clays. Geofluids. 2021; 2021 ():1-15.
Chicago/Turabian StyleMinghong Sheng; Jingjing Gao; Panpan Guo; Rihong Cao; Yixian Wang. 2021. "Temporal-Spatial Characteristics of Ground and Pile Responses to Twin Shield Tunneling in Clays." Geofluids 2021, no. : 1-15.
Due to the complexity of the interaction between the geogrid and the soil interface in high earth-rock dams, the method of replacing the grid with steel bars may neglect the interaction between the geogrid and the soil. The finite difference software FLAC3D is applied, and the geogrid element is used to simulate the geogrid and the coupling interface. Then, the deformation value of the dam under the action of the earthquake is obtained by calculation; the potential slip surface position is calculated and analyzed; by developing a safety factor time history calculation method using FISH language, the safety factor time history curve is obtained. The calculation results: after the high earth-rock dam is reinforced by reasonable layout, the deformation of the dam body is reduced, the sliding surface of the dam slope is moved down, the safety factor is increased, and the reinforcement effect is obvious. Through the engineering example of Shuangjiangkou core wall dam, the rationality and applicability of geogrid-reinforced high earth-rock dams are verified. The research results provide a theoretical basis for the seismic safety evaluation and reinforcement measures of high earth-rock dams.
Yalin Zhu; Chi Ma; Kun Tan; Juxiang Chen; Yixian Wang. Dynamic Response and Mechanical Behaviours of Geogrid for High Earth-rockfill Dams. Geotechnical and Geological Engineering 2021, 1 -14.
AMA StyleYalin Zhu, Chi Ma, Kun Tan, Juxiang Chen, Yixian Wang. Dynamic Response and Mechanical Behaviours of Geogrid for High Earth-rockfill Dams. Geotechnical and Geological Engineering. 2021; ():1-14.
Chicago/Turabian StyleYalin Zhu; Chi Ma; Kun Tan; Juxiang Chen; Yixian Wang. 2021. "Dynamic Response and Mechanical Behaviours of Geogrid for High Earth-rockfill Dams." Geotechnical and Geological Engineering , no. : 1-14.
This paper presents an investigation to estimate the minimum cover depth of underwater shield tunnels. Five different conventional methods for minimum cover depth estimation were reviewed and validated based on a case history of underwater shield tunneling in the Swan Lake in Hefei, China. It was found that the Japanese minimum seepage water volume (JMSWV) method and the mechanical equilibrium (ME) method are effective, and fulfill the upper and lower limits of the reasonable minimum cover depth. Afterwards, the reasonable minimum cover depth was determined by performing three-dimensional finite difference analysis considering the fluid-mechanical interaction of the ground and tunnel lining responses at different cover depths estimated by the conventional methods. The analysis indicates a consistent pattern of the cover depth effect on ground surface settlement, subsurface vertical displacement, pore water pressure, tunnel lining horizontal displacement, bending moment, and major principal stress, when the cover depth increases from 2.3 m to 6.8 m. However, for the tunnel lining vertical displacements at the tunnel vault and the tunnel bottom, the pattern of the cover depth effect reverses at an intermediate cover depth (5 m). Based on the analysis, a new procedure combining the appropriate conventional methods and numerical analysis was proposed to estimate the reasonable minimum cover depth of an underwater shield tunnel.
Panpan Guo; Xiaonan Gong; Yixian Wang; Hang Lin; Yanlin Zhao. Minimum cover depth estimation for underwater shield tunnels. Tunnelling and Underground Space Technology 2021, 115, 104027 .
AMA StylePanpan Guo, Xiaonan Gong, Yixian Wang, Hang Lin, Yanlin Zhao. Minimum cover depth estimation for underwater shield tunnels. Tunnelling and Underground Space Technology. 2021; 115 ():104027.
Chicago/Turabian StylePanpan Guo; Xiaonan Gong; Yixian Wang; Hang Lin; Yanlin Zhao. 2021. "Minimum cover depth estimation for underwater shield tunnels." Tunnelling and Underground Space Technology 115, no. : 104027.
To study the damage characteristics of rock mass under multi-level creep load, damage variable D was defined based on the spatio-temporal evolution characteristics of deformation modulus E, and the Kachanov damage theory is used to describe the damage evolution, then the damage evolution equation of the rock mass under multi-level creep load is obtained. Combining the damage evolution equation with the Lemaitre strain equivalence principle, the creep damage constitutive model of rock mass under multi-level creep load considering initial damage is obtained. By comparing the results of uniaxial and triaxial tests with the calculated values of the model, the rationality, reliability, application range of the model proposed in this paper is verified. According to the results of parameter inversion, obtain the relationship between damage, stress and time. Results show that time and stress are the important factors influencing the damage of rock mass under multi-level creep loading, the damage increases with time and stress level. However, the influence of time and stress on damage has a significant stress response characteristics: under low stress, the instantaneous damage Dis caused by the instantaneous stress loading is the main reason for the damage. With the increase of the load level, the main cause of the damage gradually changes from the instantaneous loading of the stress to the creep accumulation of the damage, and the greater the initial damage, the higher the time-dependent damage DiT proportion in the global damage.
Xing Zhang; Hang Lin; Yixian Wang; Yanlin Zhao. Creep damage model of rock mass under multi-level creep load based on spatio-temporal evolution of deformation modulus. Archives of Civil and Mechanical Engineering 2021, 21, 1 -16.
AMA StyleXing Zhang, Hang Lin, Yixian Wang, Yanlin Zhao. Creep damage model of rock mass under multi-level creep load based on spatio-temporal evolution of deformation modulus. Archives of Civil and Mechanical Engineering. 2021; 21 (2):1-16.
Chicago/Turabian StyleXing Zhang; Hang Lin; Yixian Wang; Yanlin Zhao. 2021. "Creep damage model of rock mass under multi-level creep load based on spatio-temporal evolution of deformation modulus." Archives of Civil and Mechanical Engineering 21, no. 2: 1-16.
This paper investigated the relationship between the strength of fractured rock and the crack propagation process. A series of uniaxial compression tests were carried out on the rock-like material specimens with single pre-fabricated flaw. Moreover, DIC (digital image correlation) technology was utilized to monitor and analyze the failure process of specimens. The initiation of each crack was defined as a key event, and the relationship between several key events and the axial load of the specimen during the crack propagation was quantitatively analyzed. The time-sequence analysis of crack propagation was also conducted by selecting benchmark points on the both sides of major cracks. It can be found that only the wing crack propagation occurs and there is no obvious shear crack before the peak strength. When the first secondary crack initiated, the specimen reached its peak strength and the wing crack just reached its critical length. Beyond the peak strength, secondary cracks initiated and coalesced rapidly, which leads to the sudden failure of fractured rock. Therefore, the peak strength of the specimen can be assessed by taking the critical length of the steadily propagating wing crack as the condition which determines whether the specimen reaches the peak strength. Furthermore, the discrete element numerical simulation was also implemented to confirm the experimental results.
Hengtao Yang; Hang Lin; Yixian Wang; Rihong Cao; Jiangteng Li; Yanlin Zhao. Investigation of the correlation between crack propagation process and the peak strength for the specimen containing a single pre-existing flaw made of rock-like material. Archives of Civil and Mechanical Engineering 2021, 21, 1 -21.
AMA StyleHengtao Yang, Hang Lin, Yixian Wang, Rihong Cao, Jiangteng Li, Yanlin Zhao. Investigation of the correlation between crack propagation process and the peak strength for the specimen containing a single pre-existing flaw made of rock-like material. Archives of Civil and Mechanical Engineering. 2021; 21 (2):1-21.
Chicago/Turabian StyleHengtao Yang; Hang Lin; Yixian Wang; Rihong Cao; Jiangteng Li; Yanlin Zhao. 2021. "Investigation of the correlation between crack propagation process and the peak strength for the specimen containing a single pre-existing flaw made of rock-like material." Archives of Civil and Mechanical Engineering 21, no. 2: 1-21.
As a new type of reinforced material, geocells are widely used in flexible reinforced retaining wall projects, and a lot of practical experience shows that the geocell retaining wall has a great effect on earthquake resistance, but theoretical research lags behind engineering practice, and the deformation and failure mechanism under earthquake need to be further studied. In this paper, we use the FLAC3D nonlinear, finite-difference method to study the failure mechanism of geocell-reinforced retaining walls under earthquake, to analyze the advantages of the geocell retaining wall in controlling deformation compared with the unreinforced retaining wall and geogrid-reinforced retaining wall, and we try to study the deformation of the reinforced wall by changing the length of the geocell and reinforcement spacing of the geocell. Research indicates the horizontal displacement of the wall edge of the reinforced retaining wall under the earthquake is slightly smaller than that of the center of the wall and the back of the wall. The geocell can effectively reduce the horizontal displacement of the retaining wall, and the effect is better than the geogrid. Increasing the length of the geocell and reducing the spacing of the geocell can effectively reduce the horizontal displacement of the retaining wall, and the effect of displacement controlling at the top of the wall is better than in other positions.
Yalin Zhu; Kun Tan; Yin Hong; Ting Tan; Manrong Song; Yixian Wang. Deformation of the Geocell Flexible Reinforced Retaining Wall under Earthquake. Advances in Civil Engineering 2021, 2021, 1 -11.
AMA StyleYalin Zhu, Kun Tan, Yin Hong, Ting Tan, Manrong Song, Yixian Wang. Deformation of the Geocell Flexible Reinforced Retaining Wall under Earthquake. Advances in Civil Engineering. 2021; 2021 ():1-11.
Chicago/Turabian StyleYalin Zhu; Kun Tan; Yin Hong; Ting Tan; Manrong Song; Yixian Wang. 2021. "Deformation of the Geocell Flexible Reinforced Retaining Wall under Earthquake." Advances in Civil Engineering 2021, no. : 1-11.
This paper proposes a new method for predicting the displacement and internal force of constructed tunnels induced by adjacent excavation with dewatering. In this method, the total excavation-induced additional stress on the constructed tunnel is derived by superposing the additional stresses induced by excavation unloading and dewatering effects. The additional stress induced by unloading effect is calculated using Mindlin’s solution. The additional stress induced by dewatering effect is calculated using the principle of effective stress and the Dupuit precipitation funnel curve. With the beam on elastic foundation method, the total additional stress is then used for calculating the tunnel displacement and internal force caused by adjacent excavation with dewatering. Based on three well-documented case histories, the performance of the proposed method is verified. Moreover, a parametric analysis is also performed to capture the effects of excavation depth, tunnel-to-excavation distance, initial water level, excavation plan view size, and specific yield on the responses of the constructed tunnels. The results indicate that the effect of excavation depth on the tunnel maximum vertical displacement, maximum bending moment, and maximum shear force is more significant at an excavation depth greater than the cover depth of the constructed tunnel. The tunnel maximum vertical displacement, maximum bending moment, and maximum shear force decrease nonlinearly with an increase in the tunnel-to-excavation distance and the initial water level. Among the investigated parameters, the excavation dimension in the tunnel longitudinal direction affects most the tunnel responses. The effect of specific yield on the tunnel displacement and internal force induced by adjacent excavation with dewatering becomes more obvious as increasing the initial water level and excavation depth.
Panpan Guo; Feifei Liu; Gang Lei; Xian Li; Cheng-Wei Zhu; Yixian Wang; Mengmeng Lu; Kang Cheng; Xiaonan Gong. Predicting Response of Constructed Tunnel to Adjacent Excavation with Dewatering. Geofluids 2021, 2021, 1 -17.
AMA StylePanpan Guo, Feifei Liu, Gang Lei, Xian Li, Cheng-Wei Zhu, Yixian Wang, Mengmeng Lu, Kang Cheng, Xiaonan Gong. Predicting Response of Constructed Tunnel to Adjacent Excavation with Dewatering. Geofluids. 2021; 2021 ():1-17.
Chicago/Turabian StylePanpan Guo; Feifei Liu; Gang Lei; Xian Li; Cheng-Wei Zhu; Yixian Wang; Mengmeng Lu; Kang Cheng; Xiaonan Gong. 2021. "Predicting Response of Constructed Tunnel to Adjacent Excavation with Dewatering." Geofluids 2021, no. : 1-17.
This paper investigates the triaxial compression behaviour of Q3 loess soil and the construction of a constitutive model accounting for the structural effect of loess on the basis of the disturbed state concept. By analyzing the triaxial compression testing results, we have established a new disturbing function with respect to the volumetric and shear moduli parameters. A research into the evolution laws of the disturbing function was also conducted, followed by the construction of a constitutive model for loess soil as well as the verification of the constitutive model with model test results. The results indicate that the double-parameter disturbing function evolves in an exponential form, capturing well the effect of moisture content and confining pressure on the loess structural behavior. The parameters of the constructed constitutive model based on the disturbed state are easy to be obtained and have clarified physical meanings. Considering the effectiveness in capturing the structural behavior of the loess, the constructed constitutive model has a great potential to be applied in the engineering practice in the loess area. The constructed constitutive model based on the disturbed state concept provides new ideas for the study of the structural constitutive model of loess, which is theoretically significant.
Yali Xu; Panpan Guo; Yixian Wang; Cheng-Wei Zhu; Kang Cheng; Gang Lei. Modelling the Triaxial Compression Behavior of Loess Using the Disturbed State Concept. Advances in Civil Engineering 2021, 2021, 1 -17.
AMA StyleYali Xu, Panpan Guo, Yixian Wang, Cheng-Wei Zhu, Kang Cheng, Gang Lei. Modelling the Triaxial Compression Behavior of Loess Using the Disturbed State Concept. Advances in Civil Engineering. 2021; 2021 ():1-17.
Chicago/Turabian StyleYali Xu; Panpan Guo; Yixian Wang; Cheng-Wei Zhu; Kang Cheng; Gang Lei. 2021. "Modelling the Triaxial Compression Behavior of Loess Using the Disturbed State Concept." Advances in Civil Engineering 2021, no. : 1-17.
In order to realize the high efficiency quality classification and three-dimensional visualization of engineering rock mass and to solve the technical difficulties of the traditional rock mass quality evaluation method such as high labor intensity, long process time consumption, many intervention processes such as scale measurement and manual calculation, and nonintuitive classification results, this paper puts forward a 3D visual rock mass quality evaluation method and system based on close-range photography, which optimizes the traditional rock mass quality evaluation method, makes the rock mass classification three-dimensional and visible, and realizes the estimation of unrevealed rock mass quality evaluation index. The research results show the following: (1) The method of storing joint information by close-range photography and extracting joint information by human-computer interaction improves the working efficiency and the process is safe and controllable compared with the traditional method of collecting fracture parameters. (2) Based on the statistical analysis of 97 groups of roadway survey data, the comprehensive statistical regression formula between BQ value of Chinese national standard and RMR value is given, and there is a good correlation between BQ value and RMR value of rock mass quality index. (3) Based on the power-inverse ratio method, the three-dimensional model of rock mass classification of the mine was established, and the cutting model obtained the current distribution diagram of rock mass quality grade, providing scientific reference for drilling, blasting, support, and other production design optimizations.
Haiping Yuan; Chenghao Chen; Yixian Wang; Hanbing Bian; Yan Liu. Joint Investigation and 3D Visual Evaluation of Rock Mass Quality. Advances in Civil Engineering 2020, 2020, 1 -16.
AMA StyleHaiping Yuan, Chenghao Chen, Yixian Wang, Hanbing Bian, Yan Liu. Joint Investigation and 3D Visual Evaluation of Rock Mass Quality. Advances in Civil Engineering. 2020; 2020 ():1-16.
Chicago/Turabian StyleHaiping Yuan; Chenghao Chen; Yixian Wang; Hanbing Bian; Yan Liu. 2020. "Joint Investigation and 3D Visual Evaluation of Rock Mass Quality." Advances in Civil Engineering 2020, no. : 1-16.
The creep characteristics of joint have an important influence on the long-term stability of rock mass engineering such as tunnels and slopes. In this paper, the sawtooth angle α is taken as the variable, five different numerical models of regular sawtooth joints are established using the discrete element numerical method, to study the shear mechanical characteristics of joints under creep condition. In addition, the shear mechanical properties of joints under transient condition are compared to analysis the influence of creep on the mechanical characteristics of joint. The results show that under shear creep condition: (1) Shear displacement of joint increases stepwise with time. At low sawtooth angles, the difference of joint shear displacement with different normal stresses is large. The long-term shear strength of joint is proportional to normal stress and sawtooth angle. (2) The total absorbed energy U and elastic energy Ue of the joint both increase as the sawtooth angle α increases. Dissipated energy Ud tends to increase first and then decrease with increasing sawtooth angle. Compared with the energy characteristics under transient condition, it is found that the joint under creep condition not only has a lower shear strength, but also requires less total absorbed energy and dissipative energy, and fewer cracks at critical failure. (3) Before the peak strength, the damage variable D increases nonlinearly with the shear displacement. Compared with the transient condition, the damage amount corresponding to the peak strength under the creep condition is smaller, and the evolution rate of the damage variable D with shear displacement at the critical failure is higher.
Xing Zhang; Hang Lin; Yixian Wang; Rui Yong; Yanlin Zhao; Shigui Du. Damage evolution characteristics of saw-tooth joint under shear creep condition. International Journal of Damage Mechanics 2020, 30, 453 -480.
AMA StyleXing Zhang, Hang Lin, Yixian Wang, Rui Yong, Yanlin Zhao, Shigui Du. Damage evolution characteristics of saw-tooth joint under shear creep condition. International Journal of Damage Mechanics. 2020; 30 (3):453-480.
Chicago/Turabian StyleXing Zhang; Hang Lin; Yixian Wang; Rui Yong; Yanlin Zhao; Shigui Du. 2020. "Damage evolution characteristics of saw-tooth joint under shear creep condition." International Journal of Damage Mechanics 30, no. 3: 453-480.
To understand crack coalescence patterns and local strain behaviors near flaw tip for flawed rock subjected to biaxial compression, a series of biaxial compression tests with a lateral stress of 2.0 MPa were carried out on rock-like specimens containing two flaws. The paper classified crack coalescence patterns, measured the local strain concentration near the flaw tip, and analyzed the stress–strain behavior related to crack initiation, propagation, and coalescence. Some interesting cracking behaviors of flawed specimens subjected to biaxial compression were observed. Seven basic crack types (wing crack, anti-wing crack, oblique and coplanar shear cracks, lateral crack, remote crack, and en echelon cracks) are identified and ten patterns of crack coalescences are observed subjected to biaxial compression. In general, the crack coalescence varies from the shear crack coalescence (S-mode) to the tensile wing crack coalescence (T-mode), and then to mixed shear/tensile crack coalescence (TS-mode), with the increase of the rock bridge ligament angle β, ranging from 25 to 120° subjected to biaxial compression. Crack initiation and coalescence usually can be reflected by a load stress rapid drop, a measured strain jump, or turning near flaw tip subjected to biaxial compression. The measured tensile or compression strains near flaw tip tend to increase almost simultaneously with higher axial stress before crack initiation; however, become very complex after crack initiation, due to the stress relaxation and adjustment near flaw tip induced by the combination of crack development and constant lateral stress. The existence of lateral stress results in many fragments in a shear failure mode with local surface spallings in flawed specimens containing two flaws.
Yanlin Zhao; Jian Liao; Yixian Wang; Qiang Liu; Hang Lin; Le Chang. Crack coalescence patterns and local strain behaviors near flaw tip for rock-like material containing two flaws subjected to biaxial compression. Arabian Journal of Geosciences 2020, 13, 1 -18.
AMA StyleYanlin Zhao, Jian Liao, Yixian Wang, Qiang Liu, Hang Lin, Le Chang. Crack coalescence patterns and local strain behaviors near flaw tip for rock-like material containing two flaws subjected to biaxial compression. Arabian Journal of Geosciences. 2020; 13 (23):1-18.
Chicago/Turabian StyleYanlin Zhao; Jian Liao; Yixian Wang; Qiang Liu; Hang Lin; Le Chang. 2020. "Crack coalescence patterns and local strain behaviors near flaw tip for rock-like material containing two flaws subjected to biaxial compression." Arabian Journal of Geosciences 13, no. 23: 1-18.
This paper investigated shear-related roughness classification based on Fuzzy comprehensive evaluation, and established a new strength model of natural rock joint. The joint profiles were extracted from 3D data to evaluate roughness, and a series of direct shear tests were carried out on three kinds of natural rock joints. The height statistical parameters Sm, Sq, Ss and Sk, and the textural statistical parameters Si, Sc, and Z2 were measured by Talysurf morphology instrument. Considering the existence of strong positive relations between Sm and Sq, and Z2 and Si, the four morphological parameters of Si, Sq, Sc, and Sk are considered as the main influencing factors related with rock joint shear behaviors. A new fracture roughness coefficient FRC is proposed based on fuzzy comprehensive evaluation (FCE), which considers that the influence of multi morphology parameters on the roughness of rock joint surface, and generally, the FRC is higher than the JRC. Compared with the previously published shear strength models, the proposed FRC-JCS shear strength model, which can more comprehensively reflect the influence of joint surface morphology parameters to shear strength, are in better agreement with the experimental data.
Yanlin Zhao; Chunshun Zhang; Yixian Wang; Hang Lin. Shear-related roughness classification and strength model of natural rock joint based on fuzzy comprehensive evaluation. International Journal of Rock Mechanics and Mining Sciences 2020, 137, 104550 .
AMA StyleYanlin Zhao, Chunshun Zhang, Yixian Wang, Hang Lin. Shear-related roughness classification and strength model of natural rock joint based on fuzzy comprehensive evaluation. International Journal of Rock Mechanics and Mining Sciences. 2020; 137 ():104550.
Chicago/Turabian StyleYanlin Zhao; Chunshun Zhang; Yixian Wang; Hang Lin. 2020. "Shear-related roughness classification and strength model of natural rock joint based on fuzzy comprehensive evaluation." International Journal of Rock Mechanics and Mining Sciences 137, no. : 104550.
Accurate prediction of surface settlements is a primary concern when deep excavations were carrying out under the water table in urban environments for the safety of the work site. The sedimentation deformation due to deep excavation of foundation pit and dewatering occurs as a result of coupling action of the two factors. The study is aimed at revealing the coupling ground response to the two factors and developing empirical correlations for estimating ground deformations. Taking a deep foundation pit of a metro station as an example, surface settlement estimations were calculated by analytical formulas and numerical models. The settlement results by analytical formulas under excavation and dewatering conditions were added linearly to the total settlements. And three-dimensional coupling numerical models were established by applying commercial software (GMS and MIDAS) to investigate the interaction impact of excavation and dewatering on the sedimentation deformation. Comparing with monitoring data, numerical simulation results match well with the monitoring data. Furthermore, an empirical surface subsidence correlation equation was developed by the polynomial fitting to illustrate the effect contribution on the total surface settlement of foundation excavation and dewatering.
Xian Li; Tingguo Zhou; Yixian Wang; Junling Han; Yanqiao Wang; Fang Tong; Delong Li; Jinmei Wen. Response Analysis of Deep Foundation Excavation and Dewatering on Surface Settlements. Advances in Civil Engineering 2020, 2020, 1 -10.
AMA StyleXian Li, Tingguo Zhou, Yixian Wang, Junling Han, Yanqiao Wang, Fang Tong, Delong Li, Jinmei Wen. Response Analysis of Deep Foundation Excavation and Dewatering on Surface Settlements. Advances in Civil Engineering. 2020; 2020 ():1-10.
Chicago/Turabian StyleXian Li; Tingguo Zhou; Yixian Wang; Junling Han; Yanqiao Wang; Fang Tong; Delong Li; Jinmei Wen. 2020. "Response Analysis of Deep Foundation Excavation and Dewatering on Surface Settlements." Advances in Civil Engineering 2020, no. : 1-10.
The natural rock mass prevailingly exists in the form of a fractured rock mass, and freezing-thawing failure of the fractured rock mass is also frequently encountered during geotechnical projects in cold regions. The previous researches and reports in freezing-thawing field principally focused on intact rocks, while rock joints and fractures were rarely considered, which causes great inconvenience to the safety design and stability assessment of engineering. In response to the special climatic conditions of cold regions, the freezing-thawing damage and degradation mechanism of fractured rock were studied in this paper based on existing laboratory experiments and damage mechanics theory. Primarily, a brief review of the progressive damage process of rock in the conventional triaxial compression experiment was given, as well as the determination methods of four characteristic stresses in the prepeak curve. Then, from the microcosmic perspective, the maximum tensile strain yield criterion was used to reflect the microunit strength which was assumed to statistically satisfy the Weibull distribution, deriving the damage evolution equation of fractured rock under the freezing-thawing cycle and load conditions and quantificationally describing the damage evolution law. Consequently, the statistical empirical constitutive relation of fractured rock considering freezing-thawing and loading damages was established. Ultimately, by combining the existing conventional triaxial compression experimental data of freezing-thawing single fractured rocks with the determination methods of characteristic stresses, the relevant constitutive parameters were solved, and the theoretical constitutive relation curves of the fractured rock after freezing-thawing cycles were obtained, which were compared with the experimental results to verify the validity of the established empirical constitutive relation. The study findings can provide a theoretical basis for revealing the freezing-thawing failure mechanism of the fractured rock mass to some extent.
Yifan Chen; Hang Lin; Yixian Wang; Yanlin Zhao. Damage Statistical Empirical Model for Fractured Rock under Freezing-Thawing Cycle and Loading. Geofluids 2020, 2020, 1 -12.
AMA StyleYifan Chen, Hang Lin, Yixian Wang, Yanlin Zhao. Damage Statistical Empirical Model for Fractured Rock under Freezing-Thawing Cycle and Loading. Geofluids. 2020; 2020 ():1-12.
Chicago/Turabian StyleYifan Chen; Hang Lin; Yixian Wang; Yanlin Zhao. 2020. "Damage Statistical Empirical Model for Fractured Rock under Freezing-Thawing Cycle and Loading." Geofluids 2020, no. : 1-12.
Geomaterials such as rock mass often have initial damage under the influence of long-term geological action and hydration corrosion environment. The initial damage affects the integrity and stability of the rock mass, resulting in a difference in the mechanical properties of jointed rock mass and intact one. Therefore, the study of the fracture and failure characteristics of the jointed rock mass is of great significance. Most of the previous researches into the fracture behavior of rock with initial damage are based on model testing, theoretical analysis, and numerical simulation of rock mass with preexisting flaws. This review concentrates on the theoretical, experimental, and numerical efforts that have been devoted to the fracture characteristics of rock or rock-like specimens with preexisting flaws under compression. Some suggestions on the future research work in this field are also given.
Hui Zhang; Panpan Guo; Yixian Wang; Yanlin Zhao; Hang Lin; Yan Liu; Yahui Shao. Fracture Behavior of Rock with Initial Damage: Theoretical, Experimental, and Numerical Investigations. Geofluids 2020, 2020, 1 -9.
AMA StyleHui Zhang, Panpan Guo, Yixian Wang, Yanlin Zhao, Hang Lin, Yan Liu, Yahui Shao. Fracture Behavior of Rock with Initial Damage: Theoretical, Experimental, and Numerical Investigations. Geofluids. 2020; 2020 ():1-9.
Chicago/Turabian StyleHui Zhang; Panpan Guo; Yixian Wang; Yanlin Zhao; Hang Lin; Yan Liu; Yahui Shao. 2020. "Fracture Behavior of Rock with Initial Damage: Theoretical, Experimental, and Numerical Investigations." Geofluids 2020, no. : 1-9.
Slope stability has been the research focus in the field of geotechnical engineering. Both the asynchronous decay speeds and distinct stability contributions of cohesion c and friction φ during slope instability have been evidenced. In this study, based on linear softening model and weighted average hypothesis, a modified double-reduction method is established. The research includes: 1) the asynchronism between decay speeds of c and φ are described by adopting different slopes in linear softening model for c and tanφ, in which case the respective reduction factors in strength reduction method Fc and Fφ are solved. 2) The distinct slope stability contributions of c and φ is readily linked with the different influences to safety factor, and therefore, introducing the equivalent influence angle θe (defined as the slope angle at which c and φ share identical contributions to stability), as well as its determination method. 3) According to weighted average hypothesis that the overall safety factor Fs is the weighted average of Fc and Fφ, the contribution scaling factor μ (defined as the weighted ratio of Fc and Fφ is proposed, which promotes the solution of respective weighted coefficients wc and wφ of two reduction factors by combining θe, achieving a new double-reduction method. 4) The validity of this method is verified via comprehensive comparison with existing double-reduction methods of practical slope examples.
Yifan Chen; Hang Lin; Yixian Wang; Rihong Cao; Chunyang Zhang; Yanlin Zhao. Modified Double-Reduction Method considering Strain Softening and Equivalent Influence Angle. KSCE Journal of Civil Engineering 2020, 24, 3257 -3266.
AMA StyleYifan Chen, Hang Lin, Yixian Wang, Rihong Cao, Chunyang Zhang, Yanlin Zhao. Modified Double-Reduction Method considering Strain Softening and Equivalent Influence Angle. KSCE Journal of Civil Engineering. 2020; 24 (11):3257-3266.
Chicago/Turabian StyleYifan Chen; Hang Lin; Yixian Wang; Rihong Cao; Chunyang Zhang; Yanlin Zhao. 2020. "Modified Double-Reduction Method considering Strain Softening and Equivalent Influence Angle." KSCE Journal of Civil Engineering 24, no. 11: 3257-3266.
The evolution laws of stress intensity factor (SIF) at the crack tip subjected to hydraulic pressure have still not elucidated clearly. This article attempts to study the evolution laws of SIF at the wing crack tip subjected to hydraulic pressure and far-field stresses, theoretically and numerically, based on the previous proposed wing crack models without considering hydraulic pressure. The numerical model of wing crack subjected to hydraulic pressure and far-field stresses is proposed by ANSYS based on finite element model (FEM). Research results show that the curves of the dimensionless SIF at the wing crack tip versus equivalent crack propagation length are in three major types: D type, DR type, and R type. The D type curve exhibits a steady propagation behavior of wing crack; however, the DR type and R type curves exhibit unsteady propagation behavior. The D type curve gradually transfers to the DR and R type curves with increasing hydraulic pressure. On the whole, the tendency of theoretical model curves is in agreement with that of numerical simulation curves. The average SSRs of HN, S, B, LK, W, and Z model solutions to SIF at the wing crack tip are 0.0079, 0.0348, 0.0099, 0.0127, 0.0077, and 0.0068, respectively. So the average SSRs of the Z and S model solutions are the lowest and highest among all theoretical model solutions. The Z model solution to SIF at the wing crack tip subjected to the combined action of hydraulic pressure and far-field stresses can be considered an optimal solution due to the lowest average SSR. The study further enhances the understanding of the mechanical behavior of hydraulic fracturing in rock mass engineering.
Yanlin Zhao; Qiang Liu; Jian Liao; Yixian Wang; Liming Tang. Theoretical and numerical models of rock wing crack subjected to hydraulic pressure and far-field stresses. Arabian Journal of Geosciences 2020, 13, 1 -14.
AMA StyleYanlin Zhao, Qiang Liu, Jian Liao, Yixian Wang, Liming Tang. Theoretical and numerical models of rock wing crack subjected to hydraulic pressure and far-field stresses. Arabian Journal of Geosciences. 2020; 13 (18):1-14.
Chicago/Turabian StyleYanlin Zhao; Qiang Liu; Jian Liao; Yixian Wang; Liming Tang. 2020. "Theoretical and numerical models of rock wing crack subjected to hydraulic pressure and far-field stresses." Arabian Journal of Geosciences 13, no. 18: 1-14.