深基坑开挖过程水平位移动态调整方法及其应用

Dynamic Adjustment Method of Horizontal Displacement for Deep Excavation and Applications

深基坑开挖过程中支护体系时常出现局部变形过大或局部应力集中的问题.文章就此提出一种地连墙内支撑支护体系动态调整方法,以解决采用长度可调节的内支撑解决支护体系难以动态调整的问题.首先通过现场实测结果验证了数值模型的可靠性,然后采用数值模拟的方法研究了该动态调节方法的可行性,单支撑长度调节条件下的支护体系受力和变形特性.结果表明:①采用可伸缩的内支撑可以实现支撑轴力和基地连墙水平位移的动态调整.②单独调节S2,S3,S4将分别引起0H〜0.6H(H为基坑深度),0.3H〜0.85H,0.5H〜1.4H高度范围内的地连墙水平位移发生变化.③单支撑调节条件下的支护体系一定存在一个受力最优点,工程实践中应将支护体系受力维持在该点附近.本文条件下的支护体系受力最优点为水平位移16.76 mm,轴力值1347.09 kN.

During the excavation of deep foundation pit,excessive local deformation or local stress concentration are often occurred in the support system.In this paper,a dynamic adjustment method of diaphragm wall internal support system is proposed,which adopts adjustable length strut to solve the problem of difficult dynamic adjustment of the support system.Firstly,the reliability of the numerical model is verified by the field measurement results,and then the feasibility of the dynamic adjustment method is studied by numerical simulation method,and the stress and deformation characteristics of the support system under the condition of single strut length adjustment are studied.The results show that:①the dynamic adjustment of the axial force and the horizontal displacement can be realized by using the retractable strut.②When S2,S3 and S4 are adjusted separately,the horizontal displacement of diaphragm wall in the height range of OH〜0.6H(H is the depth of foundation pit),O.3H〜0.85H and 0.5H〜1.4H will change.③Under the condition of single support adjustment,there must be a stress optimum point in the support system,and the stress of the support system should be maintained near this point in engineering practice,Under the condition of this paper,the best force point of support system is:horizontal displacement 16.76 mm,axial force 1347.09 kN.