复杂地质条件下基坑支护设计—滇中引水何官营倒虹吸

Design of Foundation Pit Support under Complex Geological Conditions--Taking Heguanying Inverted Siphon of Water Diversion Project in Central Yunnan as an Example

何官营倒虹吸全长1186 m,采用回填埋管形式,倒虹吸后段158 m长的管道置于饱和粉砂土层中,地下水位浅,地基存在地震液化问题,且该段线路途径东城村,周边部分房屋距离开挖基坑不足20 m,基坑开挖面临饱和粉砂土开挖边坡稳定,施工期地下水位下降,从而影响周边房屋地基稳定。为确保施工期基坑稳定和两侧房屋安全,设计将基坑防渗与支护相结合,经过方案比选后选用钢板桩支护形式。主要介绍了何官营倒虹吸钢板桩支护设计方案比选和结构结算成果。

The total length of the Heguanying inverted siphon is 1186 m,using a backfill buried pipe form.The 158 m long pipeline behind the inverted siphon is placed in a saturated sandy soil layer,with a shallow groundwater level and seismic liquefaction issues in the foundation.And this section of the route passes through Dongcheng Village,with some surrounding houses less than 20 meters away from the excavation pit.The excavation of the foundation pit faces the stability of the saturated sandy soil excavation slope,and the groundwater level drops during the construction period,which affects the stability of the surrounding building foundation.To ensure the stability of the foundation pit and the safety of buildings on both sides during the construction period,the design combines anti-seepage and support of the foundation pit.After scheme comparison,steel sheet pile support form is selected.This paper mainly introduces the design scheme comparison and structural settlement results of Heguanying inverted siphon steel sheet pile support.