单根水平旋喷桩施工引起周围土体变形的实用计算方法研究

水平旋喷桩施工期间，大量高压流体（水或水泥浆）注入土层，引起土层内部产生较大的膨胀作用，致使施工周围一定区域的土体发生变形。通过将水平旋喷桩施工过程模型化，基于Verruijt提出的半无限平面内圆孔扩张引起变形的弹性解答，提出了单根水平旋喷桩施工引起土体变形的实用计算方法。研究分析了单根水平旋喷桩施工引起土体应力状态的变化特性，给出了塑性区边界应力的计算公式；考虑水平旋喷施工参数和土性参数，应用能量原理提出了塑性区半径的计算公式。应用所提出的计算方法对水平旋喷桩施工实例进行计算分析，计算值与实测数据的对比结果验证了该计算方法的合理性。

AN APPROACH TO CALCULATE GROUND DEFORMATION INDUCED BY INSTALLATION OF SINGLE HORIZONTAL JET GROUT COLUMN

During the construction of horizontal jet grouting, the high pressurized fluids (water or grout) are injected into the soil, and it may induce expansion to the ground, which will cause significant movements of the surrounding ground. Simplified analysis of the construction process of installation of horizontal jet grout columns is perform, based on Verruijt's solution for calculating the deformation by expansion of a circular cavity with uniform radial stress in a half space, and a method for predicting ground displacements caused by installing single horizontal jet grout column is proposed in this paper. The variation of stress state due to installation of horizontal jet grout columns is investigated, and the equation for determining the stress at the interface of the plastic and the elastic zones is established. Considering the common jetting parameters and the mechanical parameters of the surrounding soil, an empirical equation is proposed for determining the radius of plastic zone based on the principle of energy. Comparison between the calculated values and field data shows that the proposed method yields a reasonable prediction.