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基于太沙基土拱效应考虑基质吸力影响的松动土压力计算模型
引用本文:蔺 港,孔令刚,詹良通,陈云敏.基于太沙基土拱效应考虑基质吸力影响的松动土压力计算模型[J].岩土力学,2015,36(7):2095-2104.
作者姓名:蔺 港  孔令刚  詹良通  陈云敏
作者单位:1. 浙江大学 岩土工程研究所,浙江 杭州 310058;2. 浙江大学 软弱土与环境土工教育部重点实验室,浙江 杭州 310058
基金项目:国家重点基金研究发展计划资助项目(No. 2012CB719805);浙江省重点创新团队支持计划资助(No. 2009R50050)。
摘    要:传统的土拱效应理论是基于上覆土体为无黏性土或饱和黏性土建立的,但非饱和状态是实际土体的常见情形,其力学特性受自然环境变化的影响。针对这一问题,基于太沙基(Terzaghi)平面土拱效应分析模型和土体单元主应力轴旋转理论,建立了考虑基质吸力的土拱效应松动土压力分析模型。依次给出了基质吸力在上覆土体内呈均匀分布、梯形分布、正三角分布和倒三角分布时的松动土压力和侧压力系数表达式。为验证该分析模型的正确性,采用FLAC建立了Trapdoor数值模型,理论计算与FLAC模拟结果非常吻合。最后,着重分析了上覆土体的饱和度、厚度、Trapdoor宽度、地下水上升和降雨等因素对松动土压力的影响。研究发现,松动土压力随土体饱和度先减小后增大,当达到进气值所对应的饱和度时松动土压力最小。

关 键 词:非饱和土  基质吸力  土拱效应  松动土压力  饱和度  
收稿时间:2014-03-26

An analytical model for loosening earth pressure considering matric suction based on Terzaghi soil arch effect
LIN Gang,KONG Ling-gang,ZHAN Liang-tong,CHEN Yun-min.An analytical model for loosening earth pressure considering matric suction based on Terzaghi soil arch effect[J].Rock and Soil Mechanics,2015,36(7):2095-2104.
Authors:LIN Gang  KONG Ling-gang  ZHAN Liang-tong  CHEN Yun-min
Institution:1. Institute of Geotechnical Engineering, Zhejiang University, Hangzhou, Zhejiang 310058, China; 2. Key Laboratory of Soft Soils and Geoenvironmental Engineering of Ministry of Education, Zhejiang University, Hangzhou, Zhejiang 310058, China
Abstract:The traditional theory of soil arch effect is developed on either cohesionless soil or saturated cohesive soil. In practice the unsaturated soils are commonly encountered, whose mechanical properties are influenced by natural environment transformation. Based on the Terzaghi’s assumption and the principle of principal stress axes rotation on soil arch effect, an analytical model is proposed to evaluate the loosening earth pressure of unsaturated soils considering matric suction. The analytical solutions of the loosening earth pressure and the lateral pressure coefficients are derived for uniform, trapezoidal, upright-triangular and reverse-triangular matric suction distributions respectively. A numerical model by FLAC is developed to verify the analytical model. The theoretical results are consistent well with the numerical results. The influences of such factors as saturation degree, thickness of overlying soil, Trapdoor width, groundwater level and rainfall, on loosening earth pressure are discussed. It is found that the loosening earth pressure decreases firstly and then increases with the saturation degree of soil increasing. The minimum loosening earth pressure is reached at the saturation degree corresponding to the air entry value of the soil.
Keywords:unsaturated soil  matric suction  soil arch effect  loosening earth pressure  saturation degree  
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