红黏土夹层对基坑边坡稳定性的影响分析

Influence of Red Clay Lens on the Stability of Deep Excavation

随着我国城市化进程的深入推进,在工程用地越来越紧张的当下,对复杂岩性组合条件下的基坑开挖变形成因进行深入研究非常有必要。对四川某基坑工程进行了工程地质分析,调查了研究区的地质环境条件。对基坑开挖前后的不同情况进行了数值计算,结果表明,在开挖前,整体受重力影响,以沉降变形为主,但沿红黏土层有横向变形的趋势,横向变形量值较小,基坑开挖后,横向变形加剧,位移量值不断加大,随着基坑开挖的不断推进,最终基坑侧壁变形持续增加,红黏土上覆岩土体沿软弱夹层不断出现剪切变形,沿基坑开挖临空面不断挤出,通过稳定性计算,发现最终处于不稳定状态。在数值计算成果的基础上,提出了工程建议,研究结论可为类似工点的勘查设计提供参考依据。

With the progressive of urbanization and the available land for the development becomes less and less.It is necessary to study the deformation of the deep excavation supporting structures in the complicated geotechnical conditions.This paper presents the evaluation results of the geotechnical and geological conditions for a deep excavation site in Sichuan.The process of the deep excavation supporting system was numerically analyzed.The results indicate that,before the excavation,the deformation of soils adjacent to the excavated area is mainly in the vertical direction under the gravity load.In the red clay lenses,horizontal deformation can be observed but the magnitude of the horizontal deformation is small.With the progress of the excavation,the horizontal deformation magnitude increases in at the excavation supporting structure,and the shear deformation along the red clay lenses increases.With squeezing of the weak red clay soil from the supporting structure and causes the instability of the supporting structure.Construction recommendations were also proposed based on the numerical evaluation results in the paper.