高压旋喷成桩对周围土体的扰动机理与控制措施研究

As jet grouting involves the injection of large volumes of high pressure grout into the soil, it can reinforce the soft clay and cause obvious disturbance on the surrounding ground, which can change the stress state of the soil and induce significant displacement. This can bring negative impact on nearby buildings or underground pipelines and will lead to the accident with any carelessness. In this study, based on the model tests of jet grouting, the theoretical analysis, the numerical analysis and analysis of field data are adopted to investigate the following issues: analyzing the mechanical response of the soil caused by jet grouting, and investigating the quantitative change law of the excess pore water pressure during jet grout under different jetting parameters; analyzing the the effect of installing the jet grouting columns on the soil displacement, and discussing the disturbance mechanism in soft clay caused by jet grouting; establishing the analysis method of soil disturbance caused by jet grouting that can consider jetting parameters and soil properties, and providing the measures to decrease the soil disturbance. It is expected that this study will extend the application of jet grouting in soft ground improvement, and reduce the adverse effects of jet grouting activity on the surrounding geological environment, and provide scientific basis for the optimization of design and construction safety of jet grouting.

高压旋喷成桩过程中，大量高压水泥浆持续注入土层，对软土地基进行加固的同时也会给周围土体带来较大的扰动，从而改变土体应力状态，致使周围土体发生变形，对附近的建筑物或者地下管线等产生一定的不利影响，稍有不慎则会引发工程事故。本项目以高压旋喷桩室内模型试验为基础，结合理论分析、数值模拟和现场实测数据分析等研究手段，分析高压旋喷桩施工扰动作用下周围土体的力学响应规律，研究不同旋喷参数条件下高压旋喷成桩引起的超孔隙水压力的定量变化规律；探讨高压旋喷成桩对周围土体的扰动机理，分析不同旋喷参数条件下高压旋喷桩施工扰动作用对周围土体位移的影响规律；建立可以考虑旋喷参数和土性条件的高压旋喷成桩引起周围土体扰动的分析方法，提出减小土体扰动的控制措施。研究成果预期可以进一步推动高压旋喷技术在软土地基加固领域的应用，减少对周边地质环境的不利影响，为高压旋喷设计优化以及施工安全保障提供科学依据。

高压旋喷成桩过程中，大量高压水泥浆持续注入土层，对软土地基进行加固的同时也会给周围土体带来较大的扰动，从而改变土体应力状态，致使周围土体发生变形，对附近的建筑物或者地下管线等产生一定的不利影响，稍有不慎则会引发工程事故。本项目通过模型试验、理论分析、数值模拟和现场实测数据分析等方法，解决了如下关键科学问题：1）揭示了高压旋喷成桩对周围土体的扰动机理，明确了不同旋喷参数条件下高压旋喷成桩引起的超孔隙水压力的定量变化规律；2）提出了高压旋喷成桩引起周围土体变形的分析方法，建立了注浆压力影响半径和注浆流量引起体积膨胀比与旋喷参数之间的定量关系；3）建立了高压旋喷成桩引起超静孔隙水压力的计算方法，提出了基于压力平衡控制原理的减小旋喷成桩扰动的控制措施。研究成果一方面可以丰富高压旋喷成桩理论研究，另一方面也可以推动高压旋喷技术在软土地基加固领域的应用，减少对周边地质环境的不利影响，为高压旋喷设计优化以及施工安全保障提供理论支撑。本项目研究成果在国家青基资助下共发表期刊论文11篇，培养研究生4名。