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将地下洞室稳定问题看作一非线性系统,研究了加卸载响应比(LURR)理论在洞室稳定分析中的应用前景及其实现途径,提出了基于地应力加卸载的实现方法。利用RFPA2D Basic软件,结合模型试验建立了平面应变数值模型,研究了加卸载实现方法,以拱顶沉降、水平收敛和声发射作为LURR参数,分析了逐级加卸载下变化特征。研究表明,拱顶沉降和收敛在荷载不太大的情况下,围岩处于稳定状态,LURR基本在1左右变化,当洞室围岩接近破坏时,拱顶沉降和水平收敛的LURR值出现震荡,不同位置处的水平收敛LURR呈现不同幅度的震荡。声发射随着荷载的增大而增加,加载声发射事件数和能量一般大于卸载情况,但未出现明显的加卸载响应。相关参数的LURR特征可用于预测洞室渐进失稳。
The stability problem of underground caverns is considered as a nonlinear system. The application foreground of the LURR theory in the stability analysis of caverns and the way to realize it are studied, and the method of loading and unloading based on ground stress is proposed. The numerical model of plane strain was established by RFPA2D Basic software combined with the model test. The method of loading and unloading was studied. The vault settlement, horizontal convergence and acoustic emission were taken as LURR parameters, and the variation characteristics under step loading and unloading were analyzed. The results show that the settlement and convergence of the vault are stable under the condition of low load, and the LURR is basically about 1. When the surrounding rock of the tunnel is close to destruction, the LURR value of vault settlement and horizontal convergence appears to oscillate , The level of convergence at different locations LURR showed different amplitude of the shock. Acoustic emission increases with the increase of load. The number of AE events and energy loading is generally larger than that of unloading, but no obvious loading / unloading response appears. The LURR feature of the relevant parameters can be used to predict the gradual instability of the cavern.