超高压水射流破岩过程中的应力波效应分析

Analysis of stress wave effect during rock breakage process by ultra-high pressure water jet

选取200,220和260MPa射流压力和3种岩样,实验研究非淹没条件下破岩效果的宏观规律.针对岩石在超高压水射流作用下的破碎特性,建立球面应力波在岩石介质中传播的波动方程.运用拉格朗日方法描述岩石质点的位移场和速度场.利用Matlab对波动方程进行计算求解,分析超高压水射流冲击下岩石破裂时序演化过程,建立岩石宏观断裂规律与微观破坏机制间的联系.研究表明:超高压水射流作用下岩石的破坏主要表现为拉伸破坏;岩石受力在应力波效应下呈现两种状态,即先拉伸后压缩应力状态与压缩应力状态;理论计算分析与实验结果基本吻合,表明利用该方法分析超高压水射流破岩机理是可行的.

Jet pressures at 200,220 and 260 MPa with three types of rock samples were selected to study the macro mechanism of rock breakage in non-submerged condition.A wave equation of spherical stress wave propagation inside the rock was established based on the breakage characteristics of rock by ultra-high pressure water jet.Lagrangian method was used to describe the displacement and velocity field of rocks.Matlab was deployed to solve the wave equation and analyze the temporal evolution process of rock breakage under ultra-high pressure,and eventually establish the relationship between macro breakage and micro damage mechanisms.Results show that rock failure by ultra high pressure water jet is primarily in the form of tensile damage.Under the impact of wave stress,two rock stress conditions exist,i.e.,firstly the tensile and compressive stress state,and then compressive state.The result of theoretical calculation agrees well with experimental data indicating that it is feasible to explain the mechanism of rock breakage by applying the stress wave theory.