XFEM和修正剑桥模型模拟高聚物劈裂注浆方法研究

Study on polymer-fracturing grouting simulations using extended finite element method and modified Cam-clay model

针对自膨胀高聚物材料在土体中劈裂扩散仿真手段尚不完备的现状,初步建立了一种模拟高聚物对土体劈裂压密作用的仿真方法。该方法采用扩展有限元离散求解区域土体介质,用修正剑桥模型描述土体力学特性,利用高聚物密度-围压关系迭代计算作用于裂缝面的浆液膨胀压力,实现了对土体劈裂缝扩展过程的数值模拟,通过与试验结果的对比验证了该方法的适用性。算例分析表明,应用该方法能够模拟膨胀力作用下土体裂缝启裂过程、扩展走向和浆脉厚度变化,获得裂缝周围土体变形模量、孔隙比、应力场和密度场分布特征,为深入研究膨胀性高聚物注浆材料对土体劈裂压密机制奠定了基础。

Previous simulation methods of the splitting diffusion of self-expanding polymer materials in soils are not complete yet.This paper develops a new,preliminary simulation method for simulating the splitting compaction effect of polymer on soil.This method uses the extended finite element method(XFEM)to solve numerically the regional soil medium,and adopts a modified Cam-clay model to describe the mechanical characteristics of the soil.And it calculates slurry expansion pressure acting on the surfaces of a soil fracture iteratively using the relationship of polymer density versus confining pressure.We realize numerical solutions of the process of crack propagation in the soil,and verify them against experimental data.Example analysis shows that the method is applicable and effective in the simulation of the soil’s crack initiation process,propagation direction,and grout vein thickness variation under the expansive force,and it gives the distribution characteristics of deformation modulus,void ratio,stress field,and density field over the soil zone around a crack,thus laying a basis for further study of the splitting compaction mechanism of expansive polymer grouting material in soil.