岩溶地区高层建筑刚性桩复合地基现场试验研究

发布时间：2018-05-18 02:32

本文选题：高层建筑 + 岩溶　；参考：《建筑结构学报》2017年06期

【摘要】：某高层建筑建造于岩溶场地,采用刚性桩复合地基。在现场开展了大型坑下综合性原位试验,包括多项载荷试验、桩与土的应力测试以及沉降观测等。运用BOTDA分布式光纤技术,获得复合地基桩身应力及桩侧摩阻力连续分布曲线。基于试验数据,对复合地基的荷载传递机制、荷载分担变化与发展规律、桩与土承载力发挥状况等进行了分析,研究了土层注浆和桩底后注浆对复合地基承载力与应力分布的影响。研究表明:增强体采用非挤土置换成桩工艺,对桩间土具有加固效果;桩底后注浆对复合地基的加固效果主要体现在加载后期的较高荷载水平下;土层注浆在提高桩间土和复合地基承载力的同时,降低了桩、土相对刚度,总体上有利于发挥土的承载作用;土层注浆对桩侧正、负摩阻力发挥均具有作用,可减少荷载经桩传递产生的下卧层附加应力,有利于下伏溶洞的安全。根据研究结果,给出了采用土层注浆时复合地基承载力发挥系数的建议值。
[Abstract]:A high-rise building is built in karst site, using rigid pile composite foundation. Comprehensive in-situ tests under large pits were carried out in the field, including a number of load tests, stress measurements of piles and soils, and settlement observations. Using BOTDA distributed fiber technology, the continuous distribution curves of pile body stress and pile side friction are obtained. Based on the experimental data, the mechanism of load transfer, the variation and development of load-sharing, and the bearing capacity of pile and soil are analyzed. The effects of soil grouting and post-pile grouting on the bearing capacity and stress distribution of composite foundation are studied. The results show that the reinforcement can reinforce the soil between piles by using non-compacting soil replacement technology, and the reinforcement effect of post-pile grouting on composite foundation is mainly reflected in the higher load level at the later stage of loading. Soil grouting not only improves the bearing capacity of soil and composite foundation, but also reduces the relative stiffness of pile and soil, which is beneficial to give full play to the bearing capacity of soil. It can reduce the additional stress of the underlying layer caused by the load transfer through the pile, which is beneficial to the safety of the underground cavern. According to the research results, the suggested value of bearing capacity coefficient of composite foundation with soil grouting is given.
【作者单位】：江苏省建筑设计研究院有限公司;东南大学土木工程学院;
【基金】：国家重点基础研究发展计划(973计划)项目(2013CB036304) 江苏省建筑设计研究院有限公司科研项目(B2017-004)
【分类号】：TU473.16

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