加劲桩配合工法桩在软土基坑中的支护效果评价

以嘉兴晶辉广场深基坑工程为背景,研究了旋喷加劲桩在软土深基坑中的支护效果。结合监测数据,利用FLAC 3D有限差分软件,对旋喷加劲桩配合SMW工法桩(劲性水泥土搅拌桩)这种组合结构在基坑各个开挖工况下的受力情况以及深层土体水平位移变化情况进行模拟计算。结果表明:深层土体水平位移曲线呈"鼓肚状",最大水平位移安全合理,位于基坑开挖底面以上1m~2m处;SMW工法桩所受剪力随开挖深度的加深而增大;三排加劲桩所受拉力呈现为越接近基坑开挖底面越大的规律。模拟结果与实际监测结果基本一致,且均在安全范围内。说明旋喷加劲桩在软土基坑中的支护效果较好,此次模型的建立较合理,为今后类似基坑工程的设计计算提供了参考。

Supporting effect evaluation of stiffening piles combined with SMW process piles in soft-soil foundation pits

Based on the deep foundation pit engineering at the Jinghui square, this work studied the effect of circumflex spray stiffening piles applied in deep foundation pits of soft soil. In combination with monitoring data, the finite difference software FLAC 3D was used to do numerical simulation of circumflex spray stiffening piles combined with SMW process piles in the thick soft soil area, and to analyze the variation of the horizontal displacement of the deep soil during excavation as well as the forces of supporting structure. The results indicate that the horizontal displacement curve of the deep soil presents a shape of "bulging", and the maximum horizontal displacement is safe and reasonable, which occurs at 1~2m above the bottom surface of the excavation. The shear force of the SMW process pile increases with the depth of excavation. The tensile forces of three row of stiffening piles grow with closer proximity to the bottom surface of the excavation. The simulation results are basically consistent with the actual monitoring results, and are all in the safe range. The results prove that the effect of circumflex spray stiffening piles in soft foundation pits is preferable and the establishment of the model is reasonable, which can provide a reference for the design and calculation of similar foundation pit construction in the future.