地连墙槽壁加固稳定性计算方法研究

Study of stability calculation method of trench face reinforcement of diaphragm wall

地连墙槽壁(以下简称"槽壁")稳定问题是地连墙施工质量和施工安全最关键的问题,由于护壁措施不当引起槽壁坍塌事故时有发生。首先,分析了槽壁失稳机制及形态,总结了各种槽壁抗失稳加固措施的优缺点,提出了深层搅拌桩(以下简称"搅拌桩")合理加固深度建议值和合理加固宽度的确定原则。其次,归纳总结了槽壁在泥浆护壁条件下各种稳定性安全系数计算方法的适用条件,探讨了各个安全系数取值的合理性,给出了建议值。最后,提出了搅拌桩加固槽壁条件下槽壁稳定性安全系数计算方法和判定标准。经多项工程实践,文中所提出的搅拌桩加固槽壁条件下槽壁稳定性安全系数计算方法和判定标准的可靠性以及加固宽度和深度的合理性得到了验证。

The stability of trench face of diaphragm wall is the most critical question in diaphragm wall construction quality and construction safety; and collapse accidents of trench face occur now and then due to inappropriate protection measure. The paper first analyzes the instability mechanism and form of trench face, and sums up both the disadvantages and advantages of every kind of anti-instability reinforcement measures for trench face. The paper also puts forward the suggestion value of rational reinforcement width and the principle of certainty of rational depth of deep mixing pile. Then, it summarizes the application conditions of every kind of stability safety factor calculation method of trench face under the terms of slurry protection, and discusses the rationality of every kind of safety factor value, and gives the recommended values. Finally, it provides the stability safety factor calculation method and decision criterion under the terms of mixing pile reinforcement. Through a number of engineering practices, the reliability of stability safety factor calculation method and stability decision criterion of trench face and both the rationality of depth as well as width under the terms of mixing pile reinforcement have been verified.