非均质砂土劈裂注浆加固机理分析

MECHANISM ANALYSIS OF SPLITTING GROUTING REINFORCEMENT IN HETEROGENEOUS SAND SOIL

由于注浆工程的隐蔽性与地质结构的自然性,劈裂-压密注浆扩散机制非常复杂,对注浆加固效果的评价认识尚不深刻。本文考虑浆脉形态与砂层结构特征,构建了注浆加固体力学计算模型,基于土力学和弹性力学的基本原理,对注浆加固效果进行了定量分析计算。通过选取特征单元体,研究了砂土压缩模量、抗剪强度及防渗性能空间各向异性特征。最后结合郑州地铁12号线砂层注浆加固工程,验证了计算方法的科学性和适用性。研究发现,砂土加固体水平和垂直方向的内摩擦角φ_(s)与φ_(c)基本一致,而水平和垂直方向的黏聚力c_(s)与c_(c),由于剪切破坏机制的不同,存在较大差别,c_(s)远小于c_(c);垂直浆脉方向的渗流机制与平行浆脉方向的渗流机制也存在差别,垂直方向的渗透系数k_(c)较水平方向的渗透系数k_(s)小4~5个数量级;平行浆脉方向的抗变形性能略高于垂直方向。本文研究成果可有效提升劈裂注浆的理论设计水平,为砂土场地工程项目建设提供科学指导。

Due to the concealment of grouting engineering and the nature of geological structures,the diffusion mechanism of splitting compaction grouting is very complex,and the evaluation of grouting reinforcement effect is not yet deeply understood.This article considers the morphology of grouting veins and the structural characteristics of sand layers,and constructs a calculation model of grouting plus solid mechanics.Based on the basic principles of soil mechanics and elastic mechanics,quantitative analysis and calculation of the grouting reinforcement effect are conducted.By selecting characteristic unit volumes,the spatial anisotropy characteristics of sand compression modulus,shear strength,and anti-seepage performance were studied.Finally,the scientific and applicability of the calculation method was verified through the sand layer grouting reinforcement project of Zhengzhou Metro Line 12.Results show that sand and solidφ_(s) andφ_(c) is basically consistent,while c_(s) and c_(c) have significant differences due to different shear failure mechanisms,with c_(s) much smaller than c_(c).There are also differences in the seepage mechanism between the vertical and parallel directions of the plasma veins,with kc being 4~5 orders of magnitude smaller than ks.The anti deformation performance in the parallel plasma direction is slightly higher than that in the vertical direction.The research results of this article can effectively improve the theoretical design level of split grouting and provide scientific guidance for the construction of sandy soil engineering projects.