1. Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing 210098, China; 2. Jiangsu Research Center for Geotechnical Engineering Technology, Hohai University, Nanjing 210098, China; 3. Geotechnical Research Institute, Hohai University, Nanjing 210098, China
Abstract：The initial shear modulus of soil G0 is an important parameter for predicting the ground deformation and dynamic response of many earth structures subjected to earthquake or explosion. Loess is spread all over the world and is usually in unsaturated state in the field. The principal objectives of this research are to investigate the initial shear modulus and pore-size distribution of an unsaturated loess by using the suction controlled resonant column tests and mercury intrusion porosimetry tests. The test results show that G0 increases with the increasing suction during drying and decreases with suction during wetting. The main reason is that the amount of large pores decreases while that of small pores increases during drying. As a result, the amount of meniscus water increases, which holds soil particles more tightly. Under the same suction, the amount of small pores is larger for specimens during wetting than that during drying, which results in stronger meniscus water effect and thus G0 during wetting is higher than that during drying.
徐洁,赵文博,陈永辉,陆嘉楠. 非饱和黄土初始剪切模量与孔径分布试验研究[J]. 岩土工程学报, 2017, 39(s1): 227-231.
XU Jie, ZHAO Wen-bo, CHEN Yong-hui, LU Jia-nan. Experimental study on initial shear modulus and pore-size distribution of unsaturated loess. Chinese J. Geot. Eng., 2017, 39(s1): 227-231.
[1] 高国瑞, 韩爱民. 论中国区域性土的分布和岩土性质的形成[J]. 岩土工程学报, 2005, 27(5): 511-515. (GAO Guo-duan, HAN Ai-min. Distribution of regional soils in China and formation of their special geotechnical properties[J]. Chinese Journal of Geotechnical Engineering, 2005, 27(5): 511-515. (in Chinese)) [2] DERJAGUIN B V, YALAMOV Y. Theory of thermophoresis of large aerosol particles[J]. Journal of Colloid Science, 1965, 20(6): 555-570. [3] WANG M, BAI X. Collapse property and microstructure of loess[J]. Geotechnical Special Publication, 2006, 111: 148. [4] 张帆宇. 黄土的剪切行为和黄土滑坡[D]. 兰州: 兰州大学, 2011. (ZHANG Fan-yu. Shear behavior of loess and loess landslides[D]. Lanzhou: Lanzhou University, 2011. (in Chinese)) [5] WU S, GRAY D H, RICHART F E Jr. Capillary effects on dynamic modulus sands and silts[J]. Journal of Geotechnical Engineering, 1984, 110(9): 1188-1203. [6] MARINHO E A M, CHANDLER R J, CRILLY M S. Stiffness measurements on an unsaturated high plasticity clay using bender elements[C]// 1st International Conference on Unsaturated Soils, UNSAT’95. Paris, 1995: 535-539. [7] PICORNELL M, NAZARIAN S. Effects of soil suction on the low-strain shear modulus of soils[C]// Proceedings of the 2nd International Conference on Unsaturated Soils, UNSAT’98. Beijing, 1998: 102-107. [8] CABARKAPA Z, CUCCOVILLO T, GUNN M. Some aspects of the pre-failure behaviour of unsaturated soil[C]// In Jamiolkowaky, Lancellotta and Lo Presti(eds.), Proceedings of II Int. Symp. On Prefailure Deformation Characteristics of Geomaterials. Torino, Balkema, 1999: 159-165. [9] MANCUSO C, VASSALLO R, D’ONOFRIO A. Soil behaviour in suction controlled cyclic and dynamic torsional shear tests[C]// Proc of 1st Asian Regional Conference on Unsaturated Soils. Singapore, 2000: 539-544. [10] MANCUSO C, VASSALLO R, D’ONOFRIO A. Small strain behavior of a silty sand in controlled-suction resonant column-torsional shear tests[J]. Canadian Geotechnical Journal, 2002, 39(1): 22-31. [11] NG C W W, YUNG S M. Determination of the anisotropic shear stiffness of an unsaturated decomposed soil[J]. Géotechnique, 2008, 58(1): 23-35. [12] NG C W W, XU J, YUNG S Y. Effects of wetting-drying and stress ratio on anisotropic stiffness of an unsaturated soil at very small strains[J]. Canadian Geotechnical Journal, 2009, 46(9): 1062-1076. [13] 徐 洁, 周 超. 干湿路径影响粉土小应变剪切模量的试验研究[J]. 岩土力学, 2015, 36(增刊1): 377-382. (XU Jie, CHAO Zhou. Experimental study of effect of wetting-drying path on small-strain shear modulus of silt[J]. Rock and Soil Mechanics, 2015, 36(S1): 377-382. (in Chinese))
