深坑地下室封闭空间复杂支撑后拆除工艺探讨

Research on Construction Technology of Post-Demolishing of Deep Foundation Pit Support in Enclosed Basement

西部山区某医院综合大楼工程地上27层,地下3层,基坑开挖深度17.58m,采用排桩+二道支撑的支护形式。为保证基坑稳定、加快工程进度及最大限度降低对周边敏感环境的影响,内支撑结构在地下室顶板封闭后拆除。支撑梁网密集,混凝土体量大,作业空间封闭狭小,周边建筑密集,拆除施工难度大,风险高。对验算楼板承载力满足施工作业的前提下,结合不同拆撑方法的特点,采用静爆+机械破除为主,静力切割+人工修凿为辅的拆除施工工艺。实践证明,该工艺有效降低噪声传播和扬尘扩散,符合绿色施工要求,基坑边缘土体及邻近建筑位移变形均在允许范围内,即保证结构安全,又不影响结构施工,加快工程进度。

Hospital complex in the western mountainous area has 27 floors and 3floors underground with a depth of 17.58m,The form of support supported by piling and two support- floors. In order to ensure the stability of foundation pit, accelerate the progress of project and minimize the impact on the peripheral sensitive environment, the inner supporting structure was removed after the basement of roof was closed. The dense inner support beam net, large concrete body, closed and small work space, dense surrounding buildings, the demolition work is difficult high risk. In calculating the floor bearing cap acity satisfy the premise of construction work, in combination with the characteristics of different support demolition, use the static explosion ＋ mechanical break is given priority to, static cutting ＋ manual repair chisel is complementary technology for support structure after-demolition. It is proved that this process can effectively reduce the noise propagation and the diffusion of dust, accord with the green construction requirement, the foundation pit edge deformation and displacement ofadj acent buildings are within the scope of the permit, namely to ensure the safety o fstructures, and shall not affect the structure construction, speedup the construction schedule.