地铁深基坑变形监测及支护结构方案优化研究

Study on Deformation Monitoring and Support Structure Optimization of Deep Foundation Pit of Subway

文中以深圳市某地铁车站基坑工程为例,对基坑开挖过程中沉降量及水平位移进行了监测分析,并基于经济性提出最佳的支护结构方案。结果表明,随着基坑工程开挖的不断推进,基坑累积沉降量不断增加,钻孔灌注桩桩身的最大水平位移不断向桩底推移,且桩身的水平位移不断增加。优化后的基坑支护结构参数最佳方案是桩直径为1.2m,混凝土强度等级为C35,桩间距和支撑间距分别为1.5.6m;优化后的支护结构工程造价为100万元,比原支护结构工程造价降低28.5%;最大水平位移达到31.2mm,比原支护结构最大水平位移提升14.3%,但仍未超过设计预警值40mm,证实了优化后的基坑支护结构施工效果依然具有合理性,施工效果良好。

Taking the foundation pit project of a subway station in Shenzhen City as an example,the paper monitored and analyzed the settle-ment and horizontal displacement during the foundation pit excavation,and proposed the best support structure scheme based on economy.The results show that with the continuous progress of foundation pit excavation,the cumulative settlement of foundation pit is increasing,the maxi-mum horizontal displacement of bored pile body is moving towards the pile bottom,and the horizontal displacement of pile body is increasing.After optimization,the optimal scheme of supporting structure parameters is pile diameter of 1.2 m,concrete strength grade of C35,pile spac-ing and support spacing of 1.5 m and 6 m respectively.The optimized supporting structure engineering cost is 1 million yuan,which is 28.5%lower than the original supporting structure engineering cost.The maximum horizontal displacement reaches 31.2 mm,which is 14.3%higher than the maximum horizontal displacement of the original supporting structure,but it still does not exceed the design warning value of 40mm,which confirms that the construction effect of the optimized foundation pit supporting structure is still reasonable and the construction effect is good.