强夯置换法支护软土基坑的模拟及应用

The Application of Dynamic Replacement in Soft Soil Foundation Pit Support

强夯置换法应用于基坑支护是一种全新的软土基坑支护理念,以青岛滨海回填软土基坑为背景,以现场试夯后重型动力触探测试成果分析强夯置换体强度参数。采用FLAC模拟强夯置换后的软土基坑支护效果。对不同的强夯置换宽度,置换深度及置换位置等参数进行模拟分析。以塑性区域发展范围及坡面位移形态来判断基坑侧壁的稳定状态。根据模拟结果,强夯置换宽度为0.5倍~0.75倍基坑时,基坑预计发生深层滑动破坏,强夯置换宽度为1.25倍基坑深度时,基坑侧壁基本稳定,仅坡面局部土体表现为塑性区域。在工程实施时,采用了1.3倍基坑深度作为强夯置换宽度,通过基坑监测数据表明,基坑侧壁稳定性良好,最大位移在容许范围内。强夯置换法是一种有效的软土基坑支护方法。

The application of dynamic replacement in foundation pit support is kind of new concept. This article adopts FLAC to simulate the dynamic replacement in soft soil foundation pit support. One coastal soft soil foundation pit in Qingdao provides the practical site. In this paper,the displacement width,displacement depth and displacement posithon of different dynamic compacthon are simulated. The strength parameters are got by in-situ test in replaced soil. The plastic area and moving character are used to judge the stability of sidewall. According to simulation results,when the width of replacement is about 0. 5 ~ 0. 75 times of pit depth,the deep sliding failure is forested to occur. When the width of replacement is about 1. 25 times of pit depth,the sidewall shows stability,with little plastic area in surface. In practical project,we adopted the width of replacement 1. 3 times of pit depth. The monitoring data shows that the max movement is acceptable. Dynamic compauthon replacement is an effecthve metlod to support soft soil foundation pit.