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The loess tends to behave in an instable manner when subjected to external loads since it is characterised by metastable structure, high porosity, and water sensitivity. Therefore, the Chinese Loess Plateau has been deemed as a landslide-prone area in northwest China. This study explores the potential use of the loess-waste straw mixture as an alternative backfill material to improve the stability of loess against shallow slope failure and functionalise the agricultural solid waste. The displacement-controlled direct shear tests aim to document the baseline shear strength parameters of the loess specimen with and without waste straw inclusion, whereas the stress-controlled direct shear tests reveal the temporal relations of horizontal and vertical displacement under given shear stresses. The increase in cohesion, induced by the effect of waste straw inclusions, contributes the most to the increase in shear strength, and it is predicted using the perpendicular model. The measured results are generally in line with the prediction. Further, the stress state at failure in a displacement-controlled direct shear test and a stress-controlled direct shear test for same specimen under equal testing conditions shows good correspondence to each other irrespective of testing method, and their results approximate a single failure envelope.
Wen-Chieh Cheng; Zhong-Fei Xue; Lin Wang; Jian Xu. Stress-Controlled Direct Shear Tests of Straw Fiber Reinforced Loess. Sustainable Civil Infrastructures 2021, 130 -162.
AMA StyleWen-Chieh Cheng, Zhong-Fei Xue, Lin Wang, Jian Xu. Stress-Controlled Direct Shear Tests of Straw Fiber Reinforced Loess. Sustainable Civil Infrastructures. 2021; ():130-162.
Chicago/Turabian StyleWen-Chieh Cheng; Zhong-Fei Xue; Lin Wang; Jian Xu. 2021. "Stress-Controlled Direct Shear Tests of Straw Fiber Reinforced Loess." Sustainable Civil Infrastructures , no. : 130-162.
Reinforcing structural members and construction materials using recycled fibers has become popular in the past decades due to sustainable development concerns. The recycled fibers as soil reinforcement elements contribute to the increase in shear strength by distributing stresses exerted in the soil along the length of the recycled fibers. Loess, widely spread over the Chinese Loess Plateau, is featured with metastable structure, large porosity, and high water sensitivity. This study presents the results of applying the large-scale stress-controlled direct shear tests on the recycled straw fiber-reinforced loess. The formation mechanism of shearing behaviour enhancement of the loess by straw fiber inclusion is revealed. The associated strain-hardening behaviour can be manifested using the dilation angle or the difference in friction angle between the large-displacement friction angle and the peak friction angle. Further, the shear strength using the displacement-controlled direct shear tests presents good correspondence with that using the stress-controlled direct shear tests. The test results explore the potential of using the recycled straw fiber-reinforced loess to protect the fragile loess environment in the northwest of China.
Zhong-Fei Xue; Wen-Chieh Cheng; Lin Wang; Geyang Song. Improvement of the Shearing Behaviour of Loess Using Recycled Straw Fiber Reinforcement. KSCE Journal of Civil Engineering 2021, 25, 3319 -3335.
AMA StyleZhong-Fei Xue, Wen-Chieh Cheng, Lin Wang, Geyang Song. Improvement of the Shearing Behaviour of Loess Using Recycled Straw Fiber Reinforcement. KSCE Journal of Civil Engineering. 2021; 25 (9):3319-3335.
Chicago/Turabian StyleZhong-Fei Xue; Wen-Chieh Cheng; Lin Wang; Geyang Song. 2021. "Improvement of the Shearing Behaviour of Loess Using Recycled Straw Fiber Reinforcement." KSCE Journal of Civil Engineering 25, no. 9: 3319-3335.
Soil contamination not only can cause environmental problems but also lead to a notable change in the mechanical properties of soil. Loess widely distributed over North-West (NW) China is featured with the metastable structure, and chemical contaminants produced especially during the rapid development of NW China in recent years seriously threaten the fragile loess environments. When exposed to chemical contaminants, the impacts on the microstructural characteristics of the loess and the resultant mechanical properties are deemed critical for land reclamation in NW China. In light of this, the microscale structural characteristics of the loess exposed to acetic acid, phosphoric acid, sodium hydroxide, and sodium sulfate respectively are studied using scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy tests. Additionally, their resultant macroscale mechanical properties are determined by direct shear tests. The deterioration mechanism regarding the microscale structural characteristics when exposed to the contaminants is revealed, and the resultant macroscale mechanical properties present a good correspondence with the deteriorated microscale structural characteristics. The findings of this work provide some guideposts for contaminated land reclamation in NW China.
Wenle Hu; Wen-Chieh Cheng; Shaojie Wen; Mizanur Rahman. Effects of chemical contamination on microscale structural characteristics of intact loess and resultant macroscale mechanical properties. CATENA 2021, 203, 105361 .
AMA StyleWenle Hu, Wen-Chieh Cheng, Shaojie Wen, Mizanur Rahman. Effects of chemical contamination on microscale structural characteristics of intact loess and resultant macroscale mechanical properties. CATENA. 2021; 203 ():105361.
Chicago/Turabian StyleWenle Hu; Wen-Chieh Cheng; Shaojie Wen; Mizanur Rahman. 2021. "Effects of chemical contamination on microscale structural characteristics of intact loess and resultant macroscale mechanical properties." CATENA 203, no. : 105361.
‘Clogging’ is a common issue encountered during tunnelling in clayey soils which can impede tunnel excavation, cause unplanned downtimes and lead to significant additional project costs. Clogging can result in a drastic reduction in performance due to reduced jacking speeds and the time needed for cleaning if it cannot be fully mitigated. The data acquired by modern tunnel boring machines (TBMs) have grown significantly in recent years presenting a substantial opportunity for the application of data-driven artificial intelligence (AI) techniques. In this study, a baseline assessment of clogging in slurry-supported pipejacking is performed using a combination of TBM parameters and semi-empirical diagrams proposed in the literature. The potential for one-class support vector machines (OCSVM), isolation forest (IForest) and robust covariance (Robcov) to assess the tendency for clogging is then explored in this work. The proposed approach is applied to a pipejacking case history in Taipei, Taiwan, involving tunnelling in soft alluvial deposits. The results highlight an exciting potential for the use of AI techniques to detect clogging during slurry-supported pipejacking.
Xue-Dong Bai; Wen-Chieh Cheng; Brian B. Sheil; Ge Li. Pipejacking clogging detection in soft alluvial deposits using machine learning algorithms. Tunnelling and Underground Space Technology 2021, 113, 103908 .
AMA StyleXue-Dong Bai, Wen-Chieh Cheng, Brian B. Sheil, Ge Li. Pipejacking clogging detection in soft alluvial deposits using machine learning algorithms. Tunnelling and Underground Space Technology. 2021; 113 ():103908.
Chicago/Turabian StyleXue-Dong Bai; Wen-Chieh Cheng; Brian B. Sheil; Ge Li. 2021. "Pipejacking clogging detection in soft alluvial deposits using machine learning algorithms." Tunnelling and Underground Space Technology 113, no. : 103908.
The Loess Plateau can be considered as a landslide-prone area in northwest China. The genera consensus about the interaction between landslide deposit and terrace sediments is not well studied; this paper summarised 40 loess landslides in the South Jingyang Platform, Shaanxi Province, China to help understand of this issue. Four of the loess landslides with high mobility have been analysed in detail. Three trenches T1, T2 and T3 dug after the loess landslides LD37, LD11 and LD38 highlighted the landslide-induced changes in geomorphology and internal geometry of geology, respectively. Furthermore, observation of upwards seepage flow on the profile of trench T3 is believed to be the trigger of the high speed, and long runout flowslides in the study area. A newly developed sandbox apparatus is used to reproduce the landslide kinematics due to a mass travelling over an inclined plane. The sandbox experiments show that the sediments are sheared and pushed upwards after the collision with the deposits. The deposits are then wrapped in a space between sediments, which tends to form the ‘sandwich’ structure. The distal sediments are thrust when the loess deposits’ kinetic energy consistently dissipates, developing the accumulated folded strata. These results reveal the deposits’ interactions with the sediments in the study area and provide key guideposts regarding prevention and mitigation of loess landslide hazards.
Wen-Chieh Cheng; Zhao Duan; Zhong-Fei Xue; Lin Wang. Sandbox modelling of interactions of landslide deposits with terrace sediments aided by field observation. Bulletin of Engineering Geology and the Environment 2021, 80, 3711 -3731.
AMA StyleWen-Chieh Cheng, Zhao Duan, Zhong-Fei Xue, Lin Wang. Sandbox modelling of interactions of landslide deposits with terrace sediments aided by field observation. Bulletin of Engineering Geology and the Environment. 2021; 80 (5):3711-3731.
Chicago/Turabian StyleWen-Chieh Cheng; Zhao Duan; Zhong-Fei Xue; Lin Wang. 2021. "Sandbox modelling of interactions of landslide deposits with terrace sediments aided by field observation." Bulletin of Engineering Geology and the Environment 80, no. 5: 3711-3731.
The Loess Plateau has been deemed as a landslide-prone area in northwest China because of the unique platform geomorphology and the wetting-induced loess collapse. The interactions of landslide deposit and terrace sediment have been under-explored in the literature. This lack of research has inhibited the prevention and mitigation of loess landslide. This study summarises a total of 40 loess landslides in the South Jingyang Platform, Shaanxi Province; 4 out of the 40 loess landslides are investigated in detail, with an emphasis on the geomorphology feature and the internal geometry of geology. While the sandbox experiments and the discrete element modelling primarily aimed to reproduce the kinetic process of landslide deposit falling from the platform edge and colliding with terrace sediments. The field observation distinguished three domains that represent varying degrees of interaction between the landslide deposit and the terrace sediments, namely push forward domain, shear up/out domain and original terrace sediment domain. The push forward domain is defined as an area completely contained the loess deposit, with most distinct surface upheaval, while the shear up/out domain is defined as an area that significantly interacts with the push forward domain and possesses remarkable evidence of interactions. The original terrace sediment is defined as an area that is thoroughly not disturbed by the interactions. The internal geometry change and the geomorphology features, induced by the interactions of the deposit with the sediments, are reproduced using the sandbox experiments and the discrete element modelling. The sediments shearing upwards and the occurrence of shear liquefaction are interpreted from perspectives of the velocity of deposit movement and the apparent friction angle. The results are deemed to be useful in enhancing our understanding about the interactions of the landslide deposit with the terrace sediments and countermeasures against loess flowslides in the study area in future.
Zhao Duan; Wen-Chieh Cheng; Jian-Bing Peng; Mizanur Rahman; Hao Tang. Interactions of landslide deposit with terrace sediments: Perspectives from velocity of deposit movement and apparent friction angle. Engineering Geology 2020, 280, 105913 .
AMA StyleZhao Duan, Wen-Chieh Cheng, Jian-Bing Peng, Mizanur Rahman, Hao Tang. Interactions of landslide deposit with terrace sediments: Perspectives from velocity of deposit movement and apparent friction angle. Engineering Geology. 2020; 280 ():105913.
Chicago/Turabian StyleZhao Duan; Wen-Chieh Cheng; Jian-Bing Peng; Mizanur Rahman; Hao Tang. 2020. "Interactions of landslide deposit with terrace sediments: Perspectives from velocity of deposit movement and apparent friction angle." Engineering Geology 280, no. : 105913.
Strata erosion in northwest China has become an engineering concern as a result of overdevelopment of land. This issue is more distinct for loess soil than other soils since it is characterised by metastable microstructure, high porosity, and water sensitivity. This study explores the potential for the use of agricultural waste straw as a recycled reinforcement material to form the enhanced shearing behaviour towards preventing instability of the loess body. The stress-strain relation and the pore pressure behaviour of Lantian loess and reinforced Lantian loess were studied using the conventional triaxial compression (CTC) stress path for three different confining pressures. Comparison with Jingyang loess and Delhi silt of similar relative fraction of silt to clay, sheared under the reduced triaxial compression (RTC) stress path and the reduced triaxial extension (RTE) stress paths, respectively, was conducted, with emphasis on strength uniqueness and critical state behaviour, to shed light on the effect of waste straw inclusions. The results indicate that the stress path in undrained compression and extension tests had a pronounced effect on the stress-strain relation of the studied soils. Insertion of the waste straw in Lantian loess restrained the development of volumetric deformation, producing higher pore pressures than Lantian loess (unreinforced). This study explores an exciting potential for the use of agricultural waste straw to prevent instability of the loess body in hilly-gullied regions of northwest China when subjected to quick surface thick fills.
Lin Wang; Wen-Chieh Cheng; Zhong-Fei Xue. The Use of Agricultural Waste Straw to Enhance Loess Shearing Behaviour: An Experimental Investigation. Advances in Materials Science and Engineering 2020, 2020, 1 -12.
AMA StyleLin Wang, Wen-Chieh Cheng, Zhong-Fei Xue. The Use of Agricultural Waste Straw to Enhance Loess Shearing Behaviour: An Experimental Investigation. Advances in Materials Science and Engineering. 2020; 2020 ():1-12.
Chicago/Turabian StyleLin Wang; Wen-Chieh Cheng; Zhong-Fei Xue. 2020. "The Use of Agricultural Waste Straw to Enhance Loess Shearing Behaviour: An Experimental Investigation." Advances in Materials Science and Engineering 2020, no. : 1-12.
Detecting sudden changes in geological conditions (e.g., karst cavern and fault zone) during tunnelling is a complex task. These changes can cause shield machines to jam or even induce geo-hazards such as water ingress and surface subsidence. Tunnelling parameters that relate closely to the surrounding geology have proliferated in recent years and present a substantial opportunity for the application of data-driven artificial intelligent (AI) techniques that can infer patterns from data without reference to known, or labelled, outcomes. This study explores the potential for support vector machines (SVM) to identify changes in soil type during tunnelling towards reducing the possibility of jamming and geo-hazard development. All tunnelling data were pre-processed to convert time series data into feature-based sub-series. A selection of the most popular parameter optimisation algorithms was explored to improve the accuracy of the AI predictions. Their relative merits were evaluated through comparisons with a recent pipejacking case history undertaken in gravel and clayey gravel soils. The results highlight an exciting potential for the use of optimisation algorithm-based SVMs to identify changes in soil conditions during pipejacking.
Wen-Chieh Cheng; Xue-Dong Bai; Brian B. Sheil; Ge Li; Fei Wang. Identifying characteristics of pipejacking parameters to assess geological conditions using optimisation algorithm-based support vector machines. Tunnelling and Underground Space Technology 2020, 106, 103592 .
AMA StyleWen-Chieh Cheng, Xue-Dong Bai, Brian B. Sheil, Ge Li, Fei Wang. Identifying characteristics of pipejacking parameters to assess geological conditions using optimisation algorithm-based support vector machines. Tunnelling and Underground Space Technology. 2020; 106 ():103592.
Chicago/Turabian StyleWen-Chieh Cheng; Xue-Dong Bai; Brian B. Sheil; Ge Li; Fei Wang. 2020. "Identifying characteristics of pipejacking parameters to assess geological conditions using optimisation algorithm-based support vector machines." Tunnelling and Underground Space Technology 106, no. : 103592.
Direct shear tests have been commonly used to study the frictional stresses during pipe-jacking. Particle angularity and mineralogy will influence the shear strength with apparent cohesion contributing to the arching effect during soil-structure interaction via pipe-jacking. Past researchers found it challenging to physically study particle behavior along the shear band during shearing due to the opaque nature of the equipment. This study used an original transparent shear box to conduct direct shear tests on tunneling rock spoils of sandstone and shale. Sequential images were captured during shearing and analyzed using GeoPIV software to demonstrate localized activities which were found to influence the apparent cohesion. Furthermore, the findings were successfully used to assess the arching phenomenon observed during pipe-jacking and other established pipe-jacking case studies. Rounded particles with strong mineralogy were found to be more likely to produce an arching effect as compared to angular particles with weaker minerals.
M.I. Peerun; D.E.L. Ong; C.S. Choo; W.C. Cheng. Effect of interparticle behavior on the development of soil arching in soil-structure interaction. Tunnelling and Underground Space Technology 2020, 106, 103610 .
AMA StyleM.I. Peerun, D.E.L. Ong, C.S. Choo, W.C. Cheng. Effect of interparticle behavior on the development of soil arching in soil-structure interaction. Tunnelling and Underground Space Technology. 2020; 106 ():103610.
Chicago/Turabian StyleM.I. Peerun; D.E.L. Ong; C.S. Choo; W.C. Cheng. 2020. "Effect of interparticle behavior on the development of soil arching in soil-structure interaction." Tunnelling and Underground Space Technology 106, no. : 103610.
The proliferation of data collected by modern tunnel boring machines presents a substantial opportunity for the application of data-driven anomaly detection (AD) techniques that can adapt dynamically to site specific conditions. Based on jacking forces measured during microtunneling, this paper explores the potential for AD methods to provide a more accurate and robust detection of incipient faults. A selection of the most popular AD methods proposed in the literature, comprising both clustering- and regression-based techniques, are considered for this purpose. The relative merits of each approach is assessed through comparisons to three microtunneling case histories in which anomalous jacking force behavior was encountered. The results highlight an exciting potential for the use of anomaly detection techniques to reduce unplanned downtimes and operation costs.
Brian B. Sheil; Stephen K. Suryasentana; Wen-Chieh Cheng. Assessment of Anomaly Detection Methods Applied to Microtunneling. Journal of Geotechnical and Geoenvironmental Engineering 2020, 146, 04020094 .
AMA StyleBrian B. Sheil, Stephen K. Suryasentana, Wen-Chieh Cheng. Assessment of Anomaly Detection Methods Applied to Microtunneling. Journal of Geotechnical and Geoenvironmental Engineering. 2020; 146 (9):04020094.
Chicago/Turabian StyleBrian B. Sheil; Stephen K. Suryasentana; Wen-Chieh Cheng. 2020. "Assessment of Anomaly Detection Methods Applied to Microtunneling." Journal of Geotechnical and Geoenvironmental Engineering 146, no. 9: 04020094.
The response of tunnel liner forces to the construction of very close-proximity tunnels is rather complex and depends upon ground deformability, liner joint configuration, intersection angle of new tunnel construction. A consensus with respect to securing the safety of very close-proximity tunnelling has not yet reached. This study characterised the response of tunnel liner forces to the excavation of very close-proximity tunnels, with reference to the field measurements and 2D numerical simulations. The very close-proximity tunnelling was conducted in the soft alluvial deposits at Taipei, Taiwan where two 6.1-m diameter shield tunnels ran in parallel and then stacked each other while entering the reception shaft. The ‘belta’ and the ‘volume loss’ methods were to distribute the earth load to the liner and capture the effect of ground loss respectively and the ‘local strain’ method was to reproduce both the effect of very close-proximity tunnelling and the effect of pass-through by applying a given volumetric strain to soil clusters. The predictions against the three different phases of shield approaching to (66D distance from the Ring H), reaching (1D distance from the Ring H) and passing through (57D distance from the Ring H) the existing tunnel were compared with the field measurements respectively. The principle stress change and rotation were analysed. Parametric studies with respect to the joint number and angle, ground deformability, and rotational stiffness of joint were conducted. The critical angles for the distribution of odd number joint while aligned-inclined tunnelling in the very close proximity of the existing tunnel were suggested. The results are useful in understanding the response of tunnel liner forces to the effect of very close-proximity tunnelling and optimising the joint number and angle towards securing the safety of very close-proximity tunnelling in soft soils.
Wen-Chieh Cheng; Ge Li; Dominic E.L. Ong; Shong-Loong Chen; James C. Ni. Modelling liner forces response to very close-proximity tunnelling in soft alluvial deposits. Tunnelling and Underground Space Technology 2020, 103, 103455 .
AMA StyleWen-Chieh Cheng, Ge Li, Dominic E.L. Ong, Shong-Loong Chen, James C. Ni. Modelling liner forces response to very close-proximity tunnelling in soft alluvial deposits. Tunnelling and Underground Space Technology. 2020; 103 ():103455.
Chicago/Turabian StyleWen-Chieh Cheng; Ge Li; Dominic E.L. Ong; Shong-Loong Chen; James C. Ni. 2020. "Modelling liner forces response to very close-proximity tunnelling in soft alluvial deposits." Tunnelling and Underground Space Technology 103, no. : 103455.
This paper describes an approach for predicting the diameter of a jet-grout column using the support vector regression (SVR) technique, which is regarded as a novel learning machine based upon recent advances in statistical theory, in which the combined effects of the construction (construction methods and jetting parameters) and soil properties (soil type and shearing resistance) are considered. Four different kernel functions, namely, a linear kernel function, polynomial kernel function, radial basis kernel function, and sigmoid kernel function, are integrated into the SVR technique. A large amount of field measured data on the diameter of jet-grout column are retrieved from the published literature for training and testing purposes. The results indicate that the SVR technique with a radial basis kernel function provides predictions closest to the measured results, whereas the prepared design charts enable the ability to significantly widen the application of the proposed approach to the areas of ground improvement and environmental protection.
Zhi-Feng Wang; Wen-Chieh Cheng. Predicting jet-grout column diameter to mitigate the environmental impact using an artificial intelligence algorithm. Underground Space 2020, 6, 267 -280.
AMA StyleZhi-Feng Wang, Wen-Chieh Cheng. Predicting jet-grout column diameter to mitigate the environmental impact using an artificial intelligence algorithm. Underground Space. 2020; 6 (3):267-280.
Chicago/Turabian StyleZhi-Feng Wang; Wen-Chieh Cheng. 2020. "Predicting jet-grout column diameter to mitigate the environmental impact using an artificial intelligence algorithm." Underground Space 6, no. 3: 267-280.
Evaporation-induced water and solute coupled transport is a significant cause for soil salinization that leads to a series of engineering and environmental problems. In the artificial evaporation environment, including relative humidity, atmospheric temperature, atmospheric pressure, radiation intensity, and wind speed, evaporation of loess columns with sodium sulfate, temperature profile, and water and solute transport in closed and open systems were investigated. In the former case, a range of stability was noted in the lower part of the column where the heat, water, and solute coupled transport only exhibited a weak response to a specified evaporation environment. As the environment was more favorable for evaporation, or at a higher gradient of temperature, this range extended downwards, while above this range the heat, water, and salt profiles in the evaporation-affected domain changed dramatically, characterized by a basic law that solutes moved with water and were then retained with water desalinated. Evidences were found from the profiles that the water contents in the evaporation-affected range decreased but the salt contents increased, especially in the surface. In an open system, by contrast, there was little difference in temperature but greater in water and salt profiles. Three stages were found from the supply of external water during evaporation. In the initial stage, the higher gradient formed between the initial moisture state and the preset external water level led to a rapid supply of external water. As the evaporation proceeded, a relatively stable water profile was reached as the intensity of water supply approached to that of evaporation, accompanied by a continual migration of solutes towards the surface. Due to the accumulation of precipitated salts, water transport was slowed down, and the intensity of water supply decreased. The changes in soil suction may account for the above behavior.
Jian Xu; Wei Lan; Yanfeng Li; Wen-Chieh Cheng; Jun Yuan; Qinghai Tan. Evaporation-Induced Water and Solute Coupled Transport in Saline Loess Columns in Closed and Open Systems. Geofluids 2019, 2019, 1 -26.
AMA StyleJian Xu, Wei Lan, Yanfeng Li, Wen-Chieh Cheng, Jun Yuan, Qinghai Tan. Evaporation-Induced Water and Solute Coupled Transport in Saline Loess Columns in Closed and Open Systems. Geofluids. 2019; 2019 ():1-26.
Chicago/Turabian StyleJian Xu; Wei Lan; Yanfeng Li; Wen-Chieh Cheng; Jun Yuan; Qinghai Tan. 2019. "Evaporation-Induced Water and Solute Coupled Transport in Saline Loess Columns in Closed and Open Systems." Geofluids 2019, no. : 1-26.
Loess and PHW (post-harvest waste) are easily accessible in the Chinese Loess Plateau and have been widely applied to construction of residential houses that have been inhabited for decades under the effect of freeze-thaw cycles. Although many researchers have recognised that the addition of fibers to loess soil is effective in preventing soil erosion and stabilising slopes, a consensus on this claim has not been reached yet. This study investigates the shearing behaviour of the loess-PHW mixture using small-scale and large-scale direct shear (SSDS and LSDS) tests. Four typical shear stress versus horizontal displacement curves from the multiscale direct shear tests are recognised where one is featured with strain-softening shape and the other three with a strain-hardening shape. Two out of the three curves with strain-hardening shape show a gradual increase in the shear stress at additional and larger displacements, respectively, in which some factor starts to have an influence on the shearing behaviour. Comparisons of the shear strength measured in SSDS and LSDS are made, indicating that there are differences between SSDS and LSDS. The effect of PHW addition on shear strength is assessed in order to determine the optimal dosage. The improvement of shear strength is attributed to the effect of particle inter-locking, resulting from the addition of PHW to loess specimens, and takes effect as the water content surpassed a threshold, i.e., >14%, that facilitates particle rearrangement. Particle-box interaction behaviour is assessed at the same time, and the findings satisfactorily address the main cause of the gradual increase in shear stress following the curve inflection point. The improved shearing behaviour proves the ability of the loess-PHW mixture to resist the seepage force and consequently stratum erosion.
Wen-Chieh Cheng; Zhong-Fei Xue; Lin Wang; Jian Xu. Using Post-Harvest Waste to Improve Shearing Behaviour of Loess and Its Validation by Multiscale Direct Shear Tests. Applied Sciences 2019, 9, 5206 .
AMA StyleWen-Chieh Cheng, Zhong-Fei Xue, Lin Wang, Jian Xu. Using Post-Harvest Waste to Improve Shearing Behaviour of Loess and Its Validation by Multiscale Direct Shear Tests. Applied Sciences. 2019; 9 (23):5206.
Chicago/Turabian StyleWen-Chieh Cheng; Zhong-Fei Xue; Lin Wang; Jian Xu. 2019. "Using Post-Harvest Waste to Improve Shearing Behaviour of Loess and Its Validation by Multiscale Direct Shear Tests." Applied Sciences 9, no. 23: 5206.
Since the prevention and mitigation of man-made hazards have been deemed to be the key in developing sustainable infrastructure during rapid urbanisation. Recent four massive water leak incidents taken place throughout subway construction in the soft alluvial deposits at Taipei and Kaohsiung, Taiwan, respectively, were reviewed and analysed in this study. The water leak incidents are initiated by the piping either through vertical joints between adjacent wall panels or through the seepage-prone weak zones within soilcrete body. The running leak can be traced using the variation in the piezometric pressure, and similar but smaller variations can also be seen from the soil layers at shallow depths. Lessons learned from this study would be useful in ensuring the highest quality on joints for diaphragm walls and mitigating the effect of ineffective overlapping of jet-grout columns on the watertight effectiveness while digging sump pit or dealing with tunnel-station interface.
Wen-Chieh Cheng; Ge Li; Nina Liu; Jian Xu; Suksun Horpibulsuk. Recent massive incidents for subway construction in soft alluvial deposits of Taiwan: A review. Tunnelling and Underground Space Technology 2019, 96, 103178 .
AMA StyleWen-Chieh Cheng, Ge Li, Nina Liu, Jian Xu, Suksun Horpibulsuk. Recent massive incidents for subway construction in soft alluvial deposits of Taiwan: A review. Tunnelling and Underground Space Technology. 2019; 96 ():103178.
Chicago/Turabian StyleWen-Chieh Cheng; Ge Li; Nina Liu; Jian Xu; Suksun Horpibulsuk. 2019. "Recent massive incidents for subway construction in soft alluvial deposits of Taiwan: A review." Tunnelling and Underground Space Technology 96, no. : 103178.
Inadequate lubrication during pipe ramming can result in exaggerated jacking force leading to damages to the jacked pipe string and adjoining properties. However, a consensus due to limited studies has not yet reached. This study describes a method that can be used to evaluate the lubrication performance by the reduction in the frictional coefficient μ as a function of injection mode, soil and lubrication natures, and pipe deviation. The results of an application of the method to a pipe ramming project in soft alluvial deposits are presented. Compared to 0.4 kPa of the 2–8 m section of the gravel, the excessive pipe deviation, while spanning through the 8-21 m section of the same gravel at Drive C, increases the frictional stress τld to 12.5 kPa, thereby reducing the reduction in the frictional coefficient μ to 71%. At Drive D, the combined effects, resulting from the excessive pipe deviation and the varying face resistance induced by driving into the 11–24 m section of clayey gravel, contribute to the growing frictional stress τld of 4.0 kPa and are deemed as being the major cause leading to the low reduction of 84%. While pipejacking through the 24–31 m section of clayey gravel, the occasional gravel leads to the inability of developing lower face resistance causing the misleading reduction of 60%. To summarise, the excessive pipe deviation and/or the varying face resistance largely affects the percentage reduction in the μ value despite the excessive volumes of injected lubricant. The occasional gravel leads to the misleading reduction.
Wen-Chieh Cheng; Ge Li. Factors Affecting Lubrication of Pipejacking in Soft Alluvial Deposits. Advancements in Geotechnical Engineering 2019, 121 -134.
AMA StyleWen-Chieh Cheng, Ge Li. Factors Affecting Lubrication of Pipejacking in Soft Alluvial Deposits. Advancements in Geotechnical Engineering. 2019; ():121-134.
Chicago/Turabian StyleWen-Chieh Cheng; Ge Li. 2019. "Factors Affecting Lubrication of Pipejacking in Soft Alluvial Deposits." Advancements in Geotechnical Engineering , no. : 121-134.
Incident often occurs while deepening excavation pit and/or tunnelling underground pipelines although serious attention from practitioners, engineers, and scientists has received. Prevention and mitigation of incident have thus been deemed to be the key in developing sustainable infrastructure in urban areas. This study analyses and discusses an extensive water leak incident taken place throughout the parallel tunnels LUO09 construction in the soft alluvial deposits in Kaohsiung, Taiwan. Dumping sand bags and quick-set cement intervened the incident but in vain. The water leak incident is initiated by the piping. The existing vehicle underpass causes the jet-grout columns installed not exactly in the plumb. Their overlapping is estimated to be less than the design value of 60 cm, and some seepage-prone weak zones are thus developed. The measured hydraulic gradient being equal to 12.1 and existence of seepage-prone weak zones are deemed as the main cause initiating the water leak incident. The pinhole test results highlight not only the nonplastic nature of the Kaohsiung silt but also its vulnerability to piping under large hydraulic gradients. Some bullet points that indicate what engineers should do or avoid are learned and summarised.
Wen-Chieh Cheng; Ge Li; Annan Zhou; Jian Xu. Rethinking the Water Leak Incident of Tunnel LUO09 to Prepare for a Challenging Future. Advances in Civil Engineering 2019, 2019, 1 -11.
AMA StyleWen-Chieh Cheng, Ge Li, Annan Zhou, Jian Xu. Rethinking the Water Leak Incident of Tunnel LUO09 to Prepare for a Challenging Future. Advances in Civil Engineering. 2019; 2019 ():1-11.
Chicago/Turabian StyleWen-Chieh Cheng; Ge Li; Annan Zhou; Jian Xu. 2019. "Rethinking the Water Leak Incident of Tunnel LUO09 to Prepare for a Challenging Future." Advances in Civil Engineering 2019, no. : 1-11.
In Northwest China, residential houses have always been constructed using the post-harvest waste (PHW) such as straw bale. The major constituents for the straw bale generally are loess, wheat straw and corn cob. Since most the residential houses have been utilised under extreme climate over decades, the phenomenon drives this study to investigate the mechanical properties of the loess-PHW mixture through a series of uniaxial compressive strength (UCS) and strain- and stress-controlled direct shear (DS) tests. The loess-PHW mixture specimens fail in ductile mode as subjected to axial loads, which indicates a good energy absorption ability. The loess-PHW mixture specimens also possess a better strength and load-carrying capacity than the loess specimens. The findings not only highlight the superior performance of the loess-PHW mixture, but also promote the development of sustainable building.
Wen-Chieh Cheng; Zhong-Fei Xue; Lin Wang. Performance Evaluation of Loess-Post Harvest Waste Mixture: Insights from Residential House on Loess Plateau, China. Proceedings of the 28th International Symposium on Mine Planning and Equipment Selection - MPES 2019 2019, 897 -908.
AMA StyleWen-Chieh Cheng, Zhong-Fei Xue, Lin Wang. Performance Evaluation of Loess-Post Harvest Waste Mixture: Insights from Residential House on Loess Plateau, China. Proceedings of the 28th International Symposium on Mine Planning and Equipment Selection - MPES 2019. 2019; ():897-908.
Chicago/Turabian StyleWen-Chieh Cheng; Zhong-Fei Xue; Lin Wang. 2019. "Performance Evaluation of Loess-Post Harvest Waste Mixture: Insights from Residential House on Loess Plateau, China." Proceedings of the 28th International Symposium on Mine Planning and Equipment Selection - MPES 2019 , no. : 897-908.
Loess, a kind of special soil, is widespread in the seasonally frozen soil regions and featured with well-developed joints and pore structure. Notwithstanding, the permeability anisotropy nature of loess can badly impact the safety of construction in such regions. Despite many influencing factors, the effect of dry density and freeze–thaw cycles plays a major role in the permeability anisotropy nature. This study uses the Global Digital Systems (GDS) triaxial permeability apparatus to investigate the permeability anisotropy nature of the Q3 horizontally and vertically cut loess specimens retrieved from an excavation pit in Xi’an, Shaanxi Province. The experimental results show that the loess possesses a distinct permeability anisotropy nature, and it is intensified when subjected to the effect of particle densification. The higher the initial moisture content, the greater the pore structure change, and the weaker the permeability anisotropy nature. The increasing cycle number promotes the growth of pore ice and subsequently the bridging pore structure, improving the pore connectivity. Despite the bridging impeding the groundwater seepage in the vertical direction, the freezing–thawing cycle of more than five times, in turn, mitigates this phenomenon, and the pore connectivity in the vertical direction outweighs the horizontal one in the end.
Jie Lu; Tie-Hang Wang; Wen-Chieh Cheng; Tao Yang; Yang Luo. Permeability Anisotropy of Loess under Influence of Dry Density and Freeze–Thaw Cycles. International Journal of Geomechanics 2019, 19, 04019103 .
AMA StyleJie Lu, Tie-Hang Wang, Wen-Chieh Cheng, Tao Yang, Yang Luo. Permeability Anisotropy of Loess under Influence of Dry Density and Freeze–Thaw Cycles. International Journal of Geomechanics. 2019; 19 (9):04019103.
Chicago/Turabian StyleJie Lu; Tie-Hang Wang; Wen-Chieh Cheng; Tao Yang; Yang Luo. 2019. "Permeability Anisotropy of Loess under Influence of Dry Density and Freeze–Thaw Cycles." International Journal of Geomechanics 19, no. 9: 04019103.
Pipejacking technologies has been extensively chosen by many mega cities worldwide to construct their sewer pipelines. Lubrication has been deemed to be the key factor in manipulating the performance of pipejacking works. Inadequate lubrication during pipejacking can lead exaggerated jacking force causing damages to the jacked pipe string and adjoining properties. Due to limited studies, a consensus has not yet reached. This study gives an access of evaluating the lubrication performance via the reduction in the frictional coefficient μ and investigates the impacts of injection type, soil and lubrication natures, and misalignment on the lubrication performance for a pipejacking project in alluvial soil deposits. The effect of misalignment, while ramming through the 8–21 m section of gravel at Drive C, gears up the frictional stress τld to 12.5 kPa (compared to 0.4 kPa of the 2–8 m section of the same gravel) and reduces the reduction to 71%. While traversing through the 24–31 m section of clayey gravel at Drive D, the occasional gravel not being long enough to develop lower face resistance leads the misleading reduction of 60%. These factors have greater influences on the lubrication performance than the injection type. The presented results would be helpful in managing the lubrication performance while pipe ramming for upcoming pipejacking project.
Wen-Chieh Cheng; Lin Wang; Zhong-Fei Xue; James C. Ni; Mizanur Rahman; Arul Arulrajah. Lubrication performance of pipejacking in soft alluvial deposits. Tunnelling and Underground Space Technology 2019, 91, 102991 .
AMA StyleWen-Chieh Cheng, Lin Wang, Zhong-Fei Xue, James C. Ni, Mizanur Rahman, Arul Arulrajah. Lubrication performance of pipejacking in soft alluvial deposits. Tunnelling and Underground Space Technology. 2019; 91 ():102991.
Chicago/Turabian StyleWen-Chieh Cheng; Lin Wang; Zhong-Fei Xue; James C. Ni; Mizanur Rahman; Arul Arulrajah. 2019. "Lubrication performance of pipejacking in soft alluvial deposits." Tunnelling and Underground Space Technology 91, no. : 102991.