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由于土体的低应变性态对深基坑施工引起的变形问题影响显著,采用常规三轴试验指标进行数值模拟得到的基坑变形一般较实测数据要大。采用最常用的摩尔库伦模型来描述软土的变形行为,以现场剪切波速试验来测定软土在低应变时的弹性模量,采用数值模拟方法研究了深基坑开挖引起的连续墙变形和地表沉降问题,研究结果表明:采用低应变强度指标(Es)得到的数值模拟成果要较采用常规三轴试验指标(E)得到的成果更符合现场监测成果;采用Es指标得到的地表沉降的最大值及出现位置与实测非常一致,但变形规律存在差异;采用Es指标得到的连续墙变形在坑底以上较实测值稍小,而以下则偏大。研究结论对软土深基坑变形的数值分析有一定的参考价值。
Because of the low strain state of soil, the deformation of deep foundation pit has a significant influence on the deformation problems. The deformation of foundation pit obtained by numerical simulation using conventional triaxial tests is generally larger than the measured data. The most commonly used Mohr-Coulomb model is used to describe the deformation behavior of soft soil. The field shear wave velocity test is used to determine the elastic modulus of soft soil under low strain. Numerical simulation is used to study the deformation of continuous wall caused by deep foundation pit excavation. The results show that the numerical simulation results obtained by using low strain strength index (Es) are more in line with the results of on-site monitoring than the results obtained by conventional triaxial test (E) The maximum value and the appearance position are in good agreement with the measured ones, but the deformation laws are different. The deformation of the continuous wall obtained by using the Es index is slightly smaller than the measured value at the bottom of the pit, while the following is larger. The conclusion of the study is of certain reference value to the numerical analysis of deep foundation pit deformation in soft soil.