剪切作用下薄层充填岩石节理渗流演化规律的试验研究

As a typical kind of infilled rock joints, the thinly filled rock joints widely exist in rock masses, of which the flow characteristics play an important role on the stability and flow control of rock masses. However, few research results on this aspect have been reported up to now. Herein, thinly filled rock joints, which have different filled material, thickness to asperity height ratio and 3D surface topography, are taken as objects and direct shear tests in laboratory and numerical simulation using PFC3D are carried out, on basis of which the dilation model are obtained by considering the effects of thickness to asperity height ratio and boundary effects. Flow tests are performed on thinly filled rock joints that have subjected to different shear displacements. According to experimental results, the influences of thickness to asperity height ratio and particle size of filled material on flow through thinly filled rock joints are analyzed, on the basis of which the evolution of flow through thinly filled rock joints during shearing is achieved. Combining with the dilation model, the transport of filled material particles in thinly filled rock joints is investigated. On this basis, equivalent aperture is proposed by using flow rates equivalence. Then a theoretical model describing the evolution of flow through thinly filled rock joints during shearing is proposed and laboratory flow tests results are adopted to verify the model. The research results will not only provide reasonable models for analyses of flow problems in rock mass projects such as dam and underground cavern excavation, but also promote the progress of researches on flow in rock masses.

薄层充填节理是天然岩体中广泛分布的一类典型充填节理，其在剪切作用下的渗流特性对岩体工程稳定性和渗流控制有重要影响，但是目前关于该方面的研究成果鲜见报导。本项目通过对具有不同充填介质、充填度和表面三维形貌的薄层充填节理试件进行室内和颗粒流数值直剪试验，建立考虑充填度和边界效应的薄层充填节理剪胀模型；通过对剪动不同位移下的薄层充填节理进行渗流试验，在分析充填度和充填介质颗粒粒径对薄层充填节理渗流特性影响的基础上，研究剪切作用下薄层充填节理的渗流演化规律；结合薄层充填节理剪胀模型研究渗流过程中充填介质颗粒运移模型，在此基础上采用渗流流量等效方法计算等效隙宽，建立基于等效隙宽的薄层充填节理渗流演化模型，并通过室内渗流试验结果对该模型进行验证。项目研究成果可以为大坝、地下洞室等岩体工程的渗流分析提供合理的理论模型，也对完善节理岩体渗流理论有积极的推动作用。

薄层充填岩石节理是天然岩体中广泛存在的一类典型充填节理，其力学和渗流特性对岩体工程稳定性有重要影响。本项目针对薄层充填岩石节理，采用室内试验、数值模拟和理论分析相结合的方法，通过含Barton标准剖面线形貌特征的薄层充填岩石节理试件室内直剪试验和离散元数值直剪试验，得到薄层充填岩石节理试件的剪切应力-剪切位移曲线、剪胀曲线和破坏特征，在此基础上分析充填度、节理表面粗糙性对薄层充填岩石节理峰值抗剪强度、剪胀位移和典型破坏特征的影响，建立了考虑充填度影响的薄层充填岩石节理峰值抗剪强度模型和剪胀模型；结合非充填岩石节理在剪切过程中的隙宽变化规律，在考虑充填介质影响基础上研究了薄层充填岩石节理渗流等效隙宽计算方法，将其引入立方定理中建立了薄层充填岩石节理渗流计算模型。项目研究成果可以为岩体工程稳定性和渗流分析奠定理论基础，同时对完善现有岩体强度和渗流理论有积极的推动作用。