南京软土地区基坑墙体变形性状研究
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摘要
依托南京江北地区某线形隧道基坑,搜集了35个南京地区支挡结构加内支撑的明挖基坑案例,对南京软土地区基坑开挖的墙体变形性状进行了比较系统的探讨。研究表明:墙体的最大侧移量随基坑开挖深度的增大而明显增大,变化范围为0.05%H_e～0.69%H_e,平均值约为0.24%H_e;最大侧移深度均位于H_e-8～H_e+2之间,其中多数位于基坑开挖底面以上;南京地区侧墙变形具有显著的时空效应,施工过程应注意尽可能缩短坑底暴露时间;SMW工法支护对于墙体侧移的控制能力相比地连墙及钻孔桩支护较弱。另外,围护结构的插入比和基坑的长宽比亦会对墙体变形产生影响。
Based on a linear foundation pit in Jiangbei, Region of Nanjing, a database of 35 case histories was collected. The characteristics of lateral displacement in Nanjing due to deep excavation are studied systematically. The research shows that the maximum lateral displacement increases with the excavation depth, which ranges from 0.05%H_e to 0.69%H_e, with an average value of 0.24%H_e. The maximum lateral wall displacements along depth occur within the range from H_e-8 to H_e+2 and most are above the excavation surface. The effects of time-space characteristics are found remarkable in lateral displacement of excavation in Nanjing. Hence, the time of exposure of the pit bottom should be as short as possible in construction. The SMW engineering method is relatively weaker in restraining lateral displacement than diaphragm wall and bored pile wall. In addition,the insertion ratio and length-width ratio can both affect the lateral displacement.
Based on a linear foundation pit in Jiangbei, Region of Nanjing, a database of 35 case histories was collected. The characteristics of lateral displacement in Nanjing due to deep excavation are studied systematically. The research shows that the maximum lateral displacement increases with the excavation depth, which ranges from 0.05%H_e to 0.69%H_e, with an average value of 0.24%H_e. The maximum lateral wall displacements along depth occur within the range from H_e-8 to H_e+2 and most are above the excavation surface. The effects of time-space characteristics are found remarkable in lateral displacement of excavation in Nanjing. Hence, the time of exposure of the pit bottom should be as short as possible in construction. The SMW engineering method is relatively weaker in restraining lateral displacement than diaphragm wall and bored pile wall. In addition,the insertion ratio and length-width ratio can both affect the lateral displacement.
引文
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