【作者】 缪圆冰； 江松； 黄明； 钟祖良； 黄欣； 沈启炜；

【Author】 MIAO Yuan-bing;JIANG Song;HUANG Ming;ZHONG Zu-liang;HUANG Xin;SHEN Qi-wei;College of Civil Engineering,Fuzhou University;College of Civil Engineering,Chongqing University;China Railway 18 Bureau Group Co.,Ltd;

【机构】 福州大学土木工程学院； 重庆大学土木工程学院； 中铁十八局集团有限公司；

【摘要】 复杂地层中地连墙槽壁的稳定性直接关系到墙体的施工质量,研究土层特性及泥浆重度对槽壁局部稳定性影响具有重要意义。基于泥浆护壁槽局部失稳机制研究,构建以极限分析上限法为理论基础的失稳模型,结合非线性Mohr-Coulomb破坏准则,引入强度折减法推导得到了泥浆槽壁局部稳定安全系数和临界高度的计算公式。结合实际工程案例,运用本文方法、线性Mohr-Coulomb准则方法及Han等人方法,对比分析了槽壁局部稳定安全系数和临界高度随泥浆重度及夹层特性参数变化的影响规律。三种方法的计算安全系数均随泥浆重度的增加而增大,随软弱夹层厚度及重度的增加而减小,随夹层土体黏聚力及抗压强度的增大而增大。相同条件下本文方法对泥浆重度变化敏感性体现较好,计算安全系数合理可靠且普遍最小。与线性Mohr-Coulomb准则方法比较可知,夹层土体材料的非线性特征仅影响破坏区域的体积大小,对区域形状基本无影响。更多还原

【Abstract】 Stability of the slurry trench in complex stratum determines the quality of the diaphragm wall during the construction progress,and it is of great significant to study the influence of the unit weight of slurry and soil characters to the local stability of slurry trench.Base on the research of instability mechanics of the slurry trench,damage-instability model for the trench is presented using the maximum limit analysis method.Both local factor and critical height of the slurry trench are proposed by combining the nonlinear M-C failure criterion and strength reduction method.The approach presented in this paper is compared to other two method by applying in a project practice,and the relationships between the local factor,critical height and the unit weight of the slurry,character parameters of the soil are obtained.Results calculated by all the methods show that,safety factor increases as the increment of unit weight of slurry,cohesion and compressive stress of the soft soil,and decreased as the thickness and unit weight of the soft intercalated layer.However,the calculated results by the approach presented in this paper is sensitive to the change of unit weight of the slurry,which is closed to the phenomenon in site.The local factor is generally the minimum to the others.Furthermore,after comparing the approach presented in this paper to the method on the basis of the M-C criterion,it is indicated that the nonlinear character of the soft soil only affects the size of local failure area,not to the basic shape of it.更多还原