强夯置换法支护软土基坑的模拟及应用
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摘要
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.
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.
引文
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[2]闫续屏,吕和蔼.超高能级强夯法处理人工冲填填海地基[J].施工技术,2013(19):80~84.
[3]孙少锐,韩银龙,王亚杰.高速公路路基强夯加固机制分析[J].西华大学学报·自然科学版,2016(3):93~96.
[4]郑凌逶,周风华.强夯置换软土中碎石墩形成过程的试验研究[J].岩土力学,2014(1):90~97.
[5]刘红军,吴腾,马江等.基于孔压监测的强夯置换和砂井-强夯处理饱和软土地基试验研究[J].中国海洋大学学报·自然科学版,2015(2):109~114.
[7]郑凌逶,周风华,谢新宇.强夯置换中碎石运动机制和成墩过程的数值模拟[J].岩土工程学报,2013(11):2068~2075.
[8]李向群,杨丰年,王海鹏.强夯置换技术试验研究[J].吉林建筑大学学报,2015(3):15~18.
[9]熊信福,聂吉利,刘献刚等.柱锤强夯置换基坑支护技术在软土基坑施工中的应用[J].施工技术,2016(16):115~117.
[10]Li Qiaocao.The Deformation Behavior Analysis for Deep Foundation Pit in Soft Soil Area Considering Seepage-Consolidation Coupling[J].Advanced Materials Research,2014,3181(926).
[11]Qiping Weng,Zhonghua Xu,Zhihou Wu,et al.Design and Performance of the Deep Excavation of a Substation Constructed by top-down Method in Shanghai Soft Soils[J].Procedia Engineering,2016,165(165).