土层对土岩双元地层深基坑变形影响效应研究

Effect of soil layer on deformation of deep foundation pit in soil rock dual layer

为探究土岩双元地层中土层力学参数及其空间分布特征对深基坑施工变形规律的影响,采用ABAQUS有限元软件,建立土岩双元地层深基坑三维施工力学模型,考虑土层力学参数及土岩结合面倾斜角等因素,分析多种工况的土岩双元地层深基坑施工诱发变形的规律。研究结果表明:①土体的弹性模量越大,桩身的侧移就越小,桩身侧移曲线由单调递减变为先增后减的“鱼腹状”,最大侧移点也由桩顶不断下移;②土体的黏聚力越大,土体和桩体的侧移就越小;黏聚力在一定的安全范围内对土体的侧移影响较小;③土岩结合面结构对支护结构变形有重要影响,其倾斜角度可以改变桩侧所受到的侧向土压力。当土岩结合面斜向抗滑桩身一侧时,侧向土压力会增大,导致桩身位移和土体侧移加大,但土岩结合面对岩层及岩层部位的桩体影响不大。

To explore the effect of soil mechanical parameters and their spatial distribution characteristics on the construction deformation behavior of deep excavation construction,a three-dimensional construction mechanics model of a dual-phase soil-rock stratum deep excavation was established using ABAQUS finite element software.Various construction scenarios were analyzed to compare and study the induced deformation patterns in the dual-phase soil-rock stratum.The study considered factors such as soil stratum mechanical parameters and the inclination angle of the soil-rock interface.The research findings indicate the following:(1)As the elastic modulus of the soil increases,the lateral displacement of the pile decreases.The lateral displacement curve changes from a monotonically decreasing distribution to a"fish belly"distribution with an initial increase followed by a decrease.The maximum lateral displacement point also moves downward from the pile top.(2)As the cohesive strength of the soil increases,the lateral displacement of both the soil and the pile decreases.Within a certain safe range,the cohesive strength has a relatively small influence on soil displacement.(3)The inclination angle of the soil-rock interface significantly affects the deformation of the support structure.It can alter the lateral soil pressure exerted on the pile.When the soil-rock interface is inclined towards one side of the anti-sliding pile,it increases the lateral soil pressure,resulting in greater pile and soil displacement.The impact of the soil-rock interface on the pile within the rock layer or its vicinity is relatively small.