摘要
苏州石湖华城D6地块基坑周边环境复杂,深度达14.30m,在苏州地区尚无类似采用一道内支撑基坑的先例。对该基坑支护结构体系进行敏感性分析,并以实测结果进行验证。结果表明:采用单道支撑时,单道支撑中心深度与围护桩深层水平位移最大值呈线性关系;支撑深度的降低对控制拆撑时桩顶瞬时侧向位移是有利的;采用两道支撑时,支撑深度变化对围护桩深层水位位移有显著影响;桩径、地表超载、嵌固长度对围护桩深层水平位移的单因素敏感性依次降低,嵌固比超过0.90之后对深层水平位移基本无影响;增加支护桩的嵌固长度对提高基坑的整体稳定性是最有效的;实测周边地表沉降、坑外水位、砼支撑轴力、立柱隆起、围护桩深层水平位移满足设计要求,增加内支撑深度之后的围护桩深层水平位移计算值略大于实测值,拆撑时支护桩顶产生的侧向突变超过计算值,应引起重视。该案例为苏州地区类似基坑工程提供了有益的参考。
The surrounding environment of block D6 of Shihu Huacheng in Suzhou is complex with the depth of 14.30 m.There is no similar precedent in Suzhou where a single internal support is used.The sensitivity analysis of the supporting structure system is carried out and verified with the field tests.The results show that:when the single support is used,the support center depth has a linear relationship with the maximum value of the deep horizontal displacement of the retaining pile;the reduction of the support center depth is beneficial to the control of the instantaneous lateral displacement of the pile top when the support is removed;when two supports are used,the change of the support center depth has a significant impact on the deep horizontal displacement of the retaining pile;the single-factor sensitivity of the pile diameter,surface overload,and embedded depth to the deep horizontal displacement of the retaining pile decreases sequentially.After the embedded fixed ratio exceeds 0.90,there is basically no effect on the deep horizontal displacement.Increasing the embedded depth of retaining pile is the most effective to improve the overall stability of the foundation pit.The surrounding ground settlement,water level outside the pit,support axial force,column uplift and deep horizontal displacement of retaining piles meet the design requirements.The calculated value of deep horizontal displacement of retaining pile after increasing the support center depth is slightly larger than the measured value,and the measured value of lateral mutation at the top of supporting pile exceeds the calculated value,which should be paid attention to.This case provides a useful reference for the similar projects in Suzhou.
机构地区
江苏华岩建设有限公司
河海大学岩土工程科学研究所
出处
《工程勘察》
2021年第5期11-17,共7页
Geotechnical Investigation & Surveying
基金
苏州市建设系统科研项目(重点类2020-10)。
