深厚覆盖层交叉部位基础处理群施工关键技术分析

Key Technologies for the Construction of the Foundation Treatments at the Intersection of the Deep Overburden Layer

硬梁包水电站首部枢纽工程覆盖层深厚,地质条件复杂,地层分布不均与,地基地层为含孤(漂)、块(卵)碎砾石层。首部枢纽工程基础处理方式多且各个施工交叉影响大,存在各工序组织不利影响施工工期、交叉施工影响施工质量等问题。如何在规定时间内合理组织各基础处理施工顺序,同时消除各工序相互影响,确保工程施工质量,是该工程需要突破的关键技术难点。研究结果表明:交叉部位基础处理群施工时,应优先进行振冲碎石桩施工;在防渗体连接部位增加高喷桩有助于提升结构防渗功效;现场大功率振冲及引孔设备应与防渗墙施工场地至少保持10 m距离。以上经验可为后续类似深厚覆盖层基础处理群施工提供借鉴。

The head hub of Yingliangbao Hydropower Project has deep overburden layer,complex geological conditions and uneven stratigraphic distribution.The ground base is composed of boulders(floats),blocks(pebbles)and gravels.There are many foundation treatments that exist mutual interference for the head hub.There are problems such as adverse impact on the construction period of each process organization,and impact on the construction quality of cross construction.How to reasonably organize the construction sequence of each foundation treatment within the specified time,eliminate the mutual influence of each process and ensure the construction quality is the key technical difficulty in this project.The results show that the construction of vibrating crushed stone piles should be prioritized during the construction of the foundation treatments of the intersection.Adding high-pressure rotating piles to the connection of impermeable bodies can help improve the anti-seepage effect of the structure;the on-site high-power vibrating and piloting equipment should be kept at least 10 m away from the cut-off wall construction site.The experience mentioned above can provide reference for the construction of similar deep overburden foundation treatments.