基于联合强度的黄土主动土压力公式与计算比较  

Comparison of active earth pressure formulations of loess based on joint strength

作　　者：骆晗 李荣建[1] 刘军定[1] 霍旭挺 张真[1] 孙萍[2] LUO Han LI Rong-jian LIU Jun-ding HUO Xu-tingl ZHANG Zhen SUN Ping(Institute of Geotechnical Engineering, Xi＇an University of Technology, Xi＇an, Shaanxi 710048, China Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China)

机构地区：[1]西安理工大学岩土工程研究所,陕西西安710048 [2]中国地质科学院地质力学研究所,北京100081

出　　处：《岩土力学》2017年第7期2080-2086,2112,共8页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.41472296;No.11072193);陕西省黄土力学与工程重点实验室项目(No.14JS064);中国地质调查项目(No.12120114035901)~~

摘　　要：土压力计算问题虽然是岩土工程中的传统研究课题之一,但对于结构性黄土而言,抗剪强度和抗拉强度是结构性黄土强度特性的两个方面,因此,黄土抗拉强度在黄土土压力计算中存在的影响需要进行合理的评价。基于建立的可综合考虑黄土抗拉和抗剪特性的联合强度理论,开展了主动极限应力平衡分析,推导了主动土压力新的计算公式,对该计算公式进行了验证并与朗肯主动土压力进行了比较。研究结果表明:在主动土压力计算与比较中,基于黄土联合强度确定的主动土压力比基于传统的Mohr-Coulomb理论确定的朗肯主动土压力要大,且墙后填土拉张区开裂深度相对要小。由于Mohr-Coulomb强度理论高估了黄土的抗拉强度,导致朗肯主动土压力计算值偏小,而基于黄土抗拉强度建立的联合强度可以合理地评价黄土的主动土压力。Earth pressure is one of the traditional research subjects in geotechnical engineering. With respect to the structural loess, shear strength and tensile strength are two aspects of structural loess strength characteristics. Therefore, the impact of tensile strength of loess on the earth pressure calculation needs to be evaluated reasonably. Based on the theory of joint strength considering tension and shear properties of loess simultaneously, a new formula of active earth pressure is derived to analyze equilibrium of active limit stress state. The formula is verified and compared with Rankine＇s active earth pressure. Result shows that the active earth pressure based on the joint strength theory is larger than Rankine＇s active earth pressure determined by traditional Mohr-Coulomb theory, and the tensile crack depth of soil behind wall is relatively small. Due to the overestimation of the tensile strength in Mohr-Coulomb strength theory, the value of Rankine＇s active earth pressure is underestimated. However, the theory of joint strength based on tensile strength of loess can reasonably calculate the active earth pressure.

关 键 词：黄土 抗拉强度 联合强度公式 主动土压力 

分 类 号：TU432[建筑科学—岩土工程]