Stability Analysis and Evaluation of Soil Slope System Considering the Shear Dilatancy Effect

doi:10.3969/j.issn.1674-0696.2017.01.10

Abstract

Abstract: Based on numerical calculation examples the influence of soil expansion on earth side slope and the stability of side slope system was studied and two different views regarding dilatancy impact on slope stability were compared and these two different methods of finite element strength reduction and gravity loading method were tested and verified. The test results show that the finite element strength reduction method has its limit in stability analysis of side slope of non-associated platic earth nature and was only effective when statisfying the dilation angle less than internal friction angle in course of redcution. In addition, study was carried out regarding the view which stated that it is a safe method to take approximate dilation angle 0°. After study made on the side slope strengthened with anti-slide pile it was found that the less is the dilation angle, the less is the deflection of anti-slide pile and the maximum earth pressure acting on the pile shaft, which presented the characteristics that earth flow through pile body more easily. Hence considering from the respect of side slope safety factor, the minimum safety factor can be obtained by taking dilation angle approximately 0° , which is a safe practice. But considering from aspect of design of anti-slide pile this method is not safe. It is hence suggested that the value setting of dilation angle shall be reasonably considered by specific issue analysis according to specific conditions of slope.

Key words: geotechnical engineering, angle of dilation, slope system, anti-slide pile, factor of safety, strength reduction finite element method

摘要： 基于数值算例，研究了土体剪胀性对土质边坡以及边坡体系稳定性的影响，对比了两种关于剪胀角对边坡稳定性影响的不同观点，采用有限元强度折减法和重力加载法对两种不同方法进行验证。结果发现：有限元强度折减法在进行非关联塑性土质边坡稳定性分析时存在局限性；只有在折减的过程中满足剪胀角小于内摩擦角的条件，强度折减法的结果才是有效的。此外，针对把剪胀角近似取为0°是一种的偏于安全的做法的观点开展研究，对有抗滑桩加固的边坡体系进行研究后发现：剪胀角越小，抗滑桩的变形越小，作用在桩身上的最大土压力也越小，表现出土体更加容易“流过”桩体的特点。因此从边坡安全系数角度考虑，把剪胀角近似取为0°可以得到最小的安全系数，是一种的偏于安全的做法，但是从抗滑桩设计的角度考虑，又是一种偏于不安全的做法。建议在实际边坡工程中具体问题具体分析，合理考虑剪胀角的取值。

关键词: 岩土工程, 剪胀角, 边坡体系, 抗滑桩, 安全系数, 有限元强度折减法

CLC Number:

CHEN Xi1，ZHANG Xunwei1，2，MIAO Jianglong1，WANG Dongyong1. Stability Analysis and Evaluation of Soil Slope System Considering the Shear Dilatancy Effect[J]. Journal of Chongqing Jiaotong University(Natural Science), 2017, 36(1): 52-57.

陈曦1，张训维1，2，苗姜龙1，王冬勇1. 土体剪胀特性对土质边坡体系稳定性的影响[J]. 重庆交通大学学报（自然科学版）, 2017, 36(1): 52-57.

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