膨胀土中狭长型深基坑围护结构受力变形分析

Retaining Structure Deformation Characteristics of Long and Narrow Type Deep Foundation Pit in the Expansive Soil

扬州瘦西湖隧道下穿蜀冈-瘦西湖风景区,全长2.8 km,场区土层10 m以下分布有40~50 m左右的第四系上更新统冲洪积下蜀粘土,隧道工程主要穿越该粘土层。该粘土层蒙脱石含量较高,测试结果为硬塑,中等膨胀性。膨胀土问题是工程建设中遇到的难题之一,对于膨胀土地层,由于膨胀土开挖卸荷和遇水膨胀的原因,应力-应变与普通土体不同,本文结合扬州瘦西湖明挖段基坑工程,对场区内几种不同形式的围护结构受力变形特点进行分析总结,分析了膨胀土地层部分对基坑围护结构受力变形的影响,为类似工程提供借鉴。

The Yangzhou Shouxihu tunnel is undercrossing the Shugang- Shouxihu lake scenic area with total length of 2.8 km, the intensity of the soil under 10 m is distribution of about 40-50 m the diluvial clay of pleistocene series in the quaternary system, the tunnel project is mainly passing through the clay layer, the montmorillonite con- tent of clay layers is rather high, the test results show the clay is hard plastic with moderate expansion. The problem of expansive soil is one of the problems we encountered in project construction, as for the expansion layer, due to the expansion because of water and the soil excavation unloading, its stress and strain is different from those of ordinary soil. In this paper, combined with the open cut period of foundation pit of Shouxihu lake project in Yangzhou City, deformation characteristic of several different forms of retaining structure and the expansive soil layer＇ s influence during the deformation of foundation pit retaining structure were analyzed, it provides a reference for similar projects.