多尺度岩石渗透特性的试验研究

Experimental study of permeability characteristics of multiscale rock

岩体赋存于一定地质环境中,经过漫长的地质构造作用,形成由连续性状的岩石材料和非连续性状的各种地质结构面组成的复杂地质体。渗透率是影响这种复杂岩体渗透特性的重要参数之一,渗透率选择的正确与否直接关系到裂隙岩体渗流分析结果的可靠性与工程稳定性。采用室内试验的方法,结合达西定律确定裂隙岩体的渗透率。通过自行研发的5种尺寸压力室测定不同尺寸岩石试样的渗透率,得到由不同裂隙、孔洞组合的岩石试样在稳定流、非稳定流下的渗透率,并由此分析得到多尺度岩石的渗透特性。从多组试验结果中分析可得,随着岩石试样的尺寸增加,岩石的渗流通道增多,从而渗透率增大,但增大到一定程度后会趋于稳定,这一渗透规律对实际工程有指导意义。

Occurrence of rock mass in certain geological environments forms complex geologic body after a long geological tectonism. This geologic body is composed of rock material of continuous character and various geological structure planes of discontinuous character. Permeability is one of the important parameters affecting the permeability characteristics of complex rock mass. Permeability selected correctly or not is directly related to the reliability and engineering stability of the fractured rock mass seepage analysis results. Laboratory experiment methods are used to determine permeability of fractured rock mass combining with the principle of Darcy＆#39;s law. Independent development of five pressure chambers of different sizes can measure the permeability of rock specimen in different sizes. Three types of experiment include stable seepage pressure experiment, variable seepage pressure experiment in one size and variable seepage pressure experiment in five different sizes. Experiment can get the permeability of rock specimen which is combined by different fractures and holes under steady flow and unsteady flow and also the permeability characteristics of multiscale rock. This method can determine the changing law of permeability along with the rock size increasing. Conclusions can be drawn from the multiple groups of experimental results. The rock seepage channel increases along with the rock size increasing, thus the permeability increases. But the permeability will be stable until it increases to a certain extent. And also this law can play a guiding significance to engineering.