临近高速公路不良地质深基坑开挖支护技术研究

Research on Excavation and Support Technology for Deep Foundation Pits in Poor Geological Conditions Near Highways

本文依托临近高速公路不良地质深基坑的开挖,首先,对开挖深度、地质情况、外部环境综合类比,采用有限元方法,研究一、二级放坡坡率对基坑安全系数的影响规律;然后,研究开挖深度对土钉抗拔、抗拉安全系数的影响;最后,对比确定开挖支护方式。研究表明:(1)随着一、二级边坡坡率的增加,基坑边坡安全系数增加;(2)当一级边坡坡率大于1.13时,基坑边坡安全系数大于1.20,满足最小放坡要求;(3)随着开挖深度的增加,浅部土钉保持恒定,中部和下部土钉波动增加,但安全系数均满足规范要求,基坑开挖稳定安全。

This article relies on the excavation of deep foundation pits in poor geological conditions near highways.Firstly,a comprehensive analogy of excavation depth,geological conditions,and external environment is used,and finite element method is used to study the influence of first and second level slope rates on the safety factor of foundation pits.Then,the influence of excavation depth on the safety factor of soil nail pull-out and tensile strength is studied.Finally,the excavation support methods are compared and determined.Research has shown that:①With the increase of the first and second level slope ratios,the safety factor of the foundation pit slope increases.②When the slope ratio of the first level slope is greater than 1.13,the safety factor of the foundation pit slope is greater than 1.20,meeting the minimum slope requirements.③As the excavation depth increases,the shallow soil nails remain constant,while the fluctuations in the middle and lower soil nails increase.However,the safety factors meet the regulatory requirements,and the excavation of the foundation pit is stable and safe.