Loess soil deposits are widely distributed in arid and semi-arid regions and constitute about 10% of land area of the world.These soils typically have a loose honeycomb-type meta-stable structure that is susceptible t...Loess soil deposits are widely distributed in arid and semi-arid regions and constitute about 10% of land area of the world.These soils typically have a loose honeycomb-type meta-stable structure that is susceptible to a large reduction in total volume or collapse upon wetting.Collapse characteristics contribute to various problems to infrastructures that are constructed on loess soils.For this reason,collapse triggering mechanism for loess soils has been of significant interest for researchers and practitioners all over the world.This paper aims at providing a state-of-the-art review on collapse mechanism with special reference to loess soil deposits.The collapse mechanism studies are summarized under three different categories,i.e.traditional approaches,microstructure approach,and soil mechanics-based approaches.The traditional and microstructure approaches for interpreting the collapse behavior are comprehensively summarized and critically reviewed based on the experimental results from the literature.The soil mechanics-based approaches proposed based on the experimental results of both compacted soils and natural loess soils are reviewed highlighting their strengths and limitations for estimating the collapse behavior.Simpler soil mechanics-based approaches with less parameters or parameters that are easy-to-determine from conventional tests are suggested for future research to better understand the collapse behavior of natural loess soils.Such studies would be more valuable for use in conventional geotechnical engineering practice applications.展开更多
How to determine reasonable position and length of anchor cable is a frequently encountered but not well addressed problem in slope reinforcement projects. In this paper, the variable-modulus elastoplastic strength re...How to determine reasonable position and length of anchor cable is a frequently encountered but not well addressed problem in slope reinforcement projects. In this paper, the variable-modulus elastoplastic strength reduction method （SRM） is used to obtain the stress field, displacement field, and factor of safety of slope. Slope reinforcement using anchor cables is modeled by surface loading, i.e. different distributions of surface loading represent various reinforcement schemes. Optimal reinforcement scheme of anchor cables can be determined based on slope stress and displacement fields. By comparing the factor of safety and stress field before and after slope reinforcement, it is found that better rein-forcement results can be achieved if strong reinforcement is applied upon the regions with high stress and large displacement. This method can well optimize the arrangement of anchor cables. In addition, several cases are employed to verify the proposed method.展开更多
基金the Chinese Scholarship Council,which funded her Joint Ph D research programthe support from Natural Sciences and Engineering Research Council of Canada(NSERC)for his research programsthe Chinese Ministry of Science and Technology for supporting his research program(grant No.2014CB744701)
文摘Loess soil deposits are widely distributed in arid and semi-arid regions and constitute about 10% of land area of the world.These soils typically have a loose honeycomb-type meta-stable structure that is susceptible to a large reduction in total volume or collapse upon wetting.Collapse characteristics contribute to various problems to infrastructures that are constructed on loess soils.For this reason,collapse triggering mechanism for loess soils has been of significant interest for researchers and practitioners all over the world.This paper aims at providing a state-of-the-art review on collapse mechanism with special reference to loess soil deposits.The collapse mechanism studies are summarized under three different categories,i.e.traditional approaches,microstructure approach,and soil mechanics-based approaches.The traditional and microstructure approaches for interpreting the collapse behavior are comprehensively summarized and critically reviewed based on the experimental results from the literature.The soil mechanics-based approaches proposed based on the experimental results of both compacted soils and natural loess soils are reviewed highlighting their strengths and limitations for estimating the collapse behavior.Simpler soil mechanics-based approaches with less parameters or parameters that are easy-to-determine from conventional tests are suggested for future research to better understand the collapse behavior of natural loess soils.Such studies would be more valuable for use in conventional geotechnical engineering practice applications.
基金funded by the National Natural Science Foundation of China (Grant Nos. 51378131 and 51378403)
文摘How to determine reasonable position and length of anchor cable is a frequently encountered but not well addressed problem in slope reinforcement projects. In this paper, the variable-modulus elastoplastic strength reduction method （SRM） is used to obtain the stress field, displacement field, and factor of safety of slope. Slope reinforcement using anchor cables is modeled by surface loading, i.e. different distributions of surface loading represent various reinforcement schemes. Optimal reinforcement scheme of anchor cables can be determined based on slope stress and displacement fields. By comparing the factor of safety and stress field before and after slope reinforcement, it is found that better rein-forcement results can be achieved if strong reinforcement is applied upon the regions with high stress and large displacement. This method can well optimize the arrangement of anchor cables. In addition, several cases are employed to verify the proposed method.
