[1]方 薇,*,周志刚,等.基于边坡离心模型试验的砂土表观粘聚力研究[J].山地学报,2017,(06):849-855.[doi:10.16089/j.cnki.1008-2786.000286]
　FANG Wei*,ZHOU Zhigang,CHEN Xiangyang,et al.Apparent Cohesion in Sandy Slope Failure under Centrifugal Test Condition[J].Mountain Research,2017,(06):849-855.[doi:10.16089/j.cnki.1008-2786.000286]
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基于边坡离心模型试验的砂土表观粘聚力研究()
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《山地学报》[ISSN:1008-2186/CN:51-1516]

卷:
期数:
2017年06期
页码:
849-855
栏目:
山地灾害
出版日期:
2017-11-30

文章信息/Info

Title:
Apparent Cohesion in Sandy Slope Failure under Centrifugal Test Condition
文章编号:
1008-2786-(2017)6-849-07
作者:
方 薇1;  2*; 周志刚1; 陈向阳1; 彭锦艺1
1.长沙理工大学 交通运输工程学院,长沙 410004; 2.长沙理工大学 道路灾变防治及交通安全教育部工程研究中心,长沙 410004
Author(s):
FANG Wei1; 2*;  ZHOU Zhigang1;  CHEN Xiangyang1;  PENG Jinyi1
1.School of Traffic and Transportation Engineering, Changsha University of Science & Technology, Changsha 410004, China; 2.Engineering Research Center of Catastrophic Prophylaxis and Treatment of Road & Traffic Safety of Ministry of Education, Changsha University of Science & Technology, Changsha 410004, China
关键词:
砂土边坡;  表观粘聚力;  离心试验;  数值模拟
Keywords:
sandy slope;  apparent cohesion;  centrifugal test;  numerical simulation
分类号:
TU411.93
DOI:
10.16089/j.cnki.1008-2786.000286
文献标志码:
A
摘要:
非饱和素砂试样的抗剪强度规律与其完全饱和或完全干燥时不相同。然而,关于含水量对离心试验条件下砂土边坡稳定性影响的研究尚未见任何报道。针对离心试验条件下不同含水量的砂质边坡稳定性的差异性,提出了低含水量砂土的表观粘聚力问题。采用TLJ-150A型土工离心实验机对由福建标准砂组成的含水量或坡角不同的四个边坡模型进行了对比试验,通过数值模拟反演了砂土抗剪强度参数,提出了基于土水特征曲线的砂土表观粘聚力计算公式和离心试验条件下的砂土表观粘聚力计算方法,并通过算例进行了部分验证。试验表明:各边坡模型均呈浅表层崩塌,对应的失稳破坏离心加速度值分别为24.6g(含水量5%,坡角75°)、35.2g(含水量2%,坡角65°)、44.3g(含水量5%,坡角65°)和40.0g(含水量8%,坡角65°); 从离心实验结束后的边坡模型中取样进行直剪试验验证了抗剪强度反演值,相对误差不超过13%。 研究表明:非饱和砂土抗剪强度的改变是由表观粘聚力引起的,表观粘聚力在一定程度上取决于基质吸力的大小,砂土表观粘聚力最大值与土水特征曲线拟合参数及有效内摩擦角有关。由离心试验获取的砂土表观粘聚力与水体质量、土体含水量和破坏g值成正比,与收缩膜周长和曲率半径成反比。
Abstract:
Unsaturated sand in a lab test exhibit distinct strength pattern from those of fully dry samples or the saturated.However, experimental investigations into the effect of soil moisture on sandy slope stability under centrifugal conditions have remained blank so far.In order to examine the alteration in stability of sandy slopes with varied water contents in centrifugal tests, this research introduced the concept of apparent cohesion for low moisture sandy soil.TLJ-150A geotechnical centrifuge for contrast test was utilized to inspect four slope models which were composed of Fujian standard sand with the designed water contents or inclinations.Then shear strength parameters were back-analyzed by numerical simulation.Calculation formula of apparent cohesion based on soil-water characteristics curve as well as centrifugal test conditions were theoretically derived and partially verified in case.Tests showed that all slope models failed in a pattern of sudden shallow collapse, while the corresponding centrifugal acceleration values in failure were 24.6 g(water content 5%, slope angle 75°), 35.2 g(water content 2%, slope angle 65°), 44.3 g(water content 5%, slope angle 65°)and 40.0 g(water content 8%, slope angle 65°).The values of shear strength obtained by back-analysis were verified by direct shear tests after centrifugal tests, with a relative error less than 13%.Results showed that the variation of shear strength of unsaturated sand was caused by apparent cohesion.Further, the apparent cohesion depended upon matric suction to some extent, and the peak value of apparent cohesion largely relied on the fitting parameters of soil water characteristic curve(SWCC)and effective friction angle.The apparent cohesion of unsaturated sand obtained by centrifugal tests was directly proportional to soil moisture content, water quality and g value in failure, and it varied inversely with the perimeter and curvature radius of shrink film.

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备注/Memo

备注/Memo:
收稿日期(Received date):2016-05-16; 改回日期(Accepted date):2016-08-17
基金项目(Foundation item):国家自然科学基金(51408059; 51374042); 道路灾变防治及交通安全教育部工程研究中心开放基金资助项目(kfj130302)[National Natural Science Foundation of China(51408059; 51374042); Open Fund of Engineering Research Center of Catastrophic Prophylaxis and Treatment of Road & Traffic Safety(Changsha University of Science & Technology), Ministry of Education(kfj130302).]
作者简介(Biography):方薇(1984-),男,湖南岳阳人,讲师,工学博士,研究方向为路基与边坡工程[Fang Wei(1984-), male, born in Yueyang of Hunan Province, lecturer, Ph.D, research on subgrade and slope engineering.] E-mail: fangwei5642366@163.com
更新日期/Last Update: 2017-11-30