摘要
为深入研究双排空心管桩作为新型支护结构在基坑工程中的变位特性,结合常州恐龙园中心广场基坑工程,选取几何相似比1∶30,完成6种工况下室内模型试验。研究表明:开挖阶段,桩后土体水平位移随入土深度逐渐增大,底部水平位移是顶部的4.2倍;加载阶段,桩后土体水平位移随入土深度先增大后减小,峰值出现在深度为3m处,底部水平位移是顶部的2.5倍。在各工况中,超载时基坑顶部水平位移是开挖的8倍,建议对基坑周边堆载情况下的桩体整体提高配筋要求,同时在施工中做好变形监测工作。前后排桩区别设计:前排桩设计强度高于后排桩;前排桩的开挖面附近和后排桩0.44h0(h0为开挖深度)的横截面提高配筋要求。建议双排空心管桩桩距采用较小的桩距,排距采用5倍桩径。理正计算所得的结果与模型试验基本一致,验证了模型试验的正确性。
Indoor model test under 6 conditions was completed in order to get a further research on the displacement performance of double hollow pile which is called as new supporting structure in the foundation pitengineering.The test selected 1 ∶30 as geometric similarity ratioand based on the foundation pit engineering of Changzhou Dinosaur Park Center Square.Research showed that when excavating,horizontal displacement of soil after pile increased with depth.The bottom horizontal displacement is 4.2 times of the top.Horizontal displacement of soil after pile increases with depth first,then decreases with depth when loading.And the peak appears at the depth of 3m.The bottom horizontal displacement is 2.5 times of the top.During each working condition,the top horizontal displacement of the foundation pit when loading is 8 times of which when excavating.When overloading around the foundation pit,improving the requirement of reinforcement of piles,strengthening the monitoring of deformation during construction is necessary.Do different design of front and back row piles: Design higher strength in front row piles than that in back row piles.The reinforcement requirements should be improved near the excavation face of the front row piles and 0.44h0( h0 is excavation depth) of back row piles.The pile spacing of double hollow pile is suggested as litter pile diameter,and the row spacing is suggested as 5 times of the pile diameter.The calculation results of Lizheng are consistent with the model test,which verified the correctness of the model test.
出处
《常州大学学报(自然科学版)》
CAS
2017年第2期78-85,共8页
Journal of Changzhou University:Natural Science Edition
基金
常州市科技局社会发展项目(CE20135038)
关键词
基坑变位
双排空心管桩
模型试验
理正软件
deformation of foundation pit
double hollow pile
model test
Lizheng software