高渗压下水岩相互作用试验研究

新研发的岩石高压渗透试验仪以静态伺服阀为主要控制元件,在脱离计算机控制条件下可使试样进水端水压保持不变。出水端水压采用调速阀控制,实现了高渗透压力下长时间的水-岩相互作用试验研究。在此基础上,提出了水-岩作用渗透液体不同时段各离子浓度变化的分析方法,并容易得到不同时段试样渗透性变化规律。为研究水-岩作用对岩石强度的影响,按基本相同条件,对该试样及未经长期水-岩渗流作用同一岩性试样进行了高渗压下的常规三轴试验,提出以试样临近破坏时的有效侧向应力大小进行强度分析,并按上述实际所加侧向压力大小及有效侧向压力大小,进行了常规饱水三轴压缩试验。试验得出,所研究蚀变岩在高渗压下水-岩作用结果与常温、常压条件测试结果类似,蚀变岩与库水的水化学反应微弱,对其自身岩体的渗透性及力学性质影响均较小。

LABORATORY TEST STUDIES OF WATER-ROCK INTERACTION UNDER HIGH SEEPAGE PRESSURE

A new laboratory equipment called High Pressure Permeability Testing Machine is used in this study.The Static Servo Valve is the main control apparatus.It can make the inlet water pressure of the sample stable when this is no computer control.The sample seepage outlet water pressure value can be controlled by speed control valve.The long time water and rock interaction test under high seepage pressure is then achieved.On the basis of this machine,this paper puts forward the different phase ion concentration studying method of water-rock reaction seepage solution.The penetrability change rule of the sample in different phases can be acquired.In order to study the rock strength characteristics influenced by water and rock reaction,with almost the same conditions,the conventional triaxial experiments under high seepage pressure have been conducted for the samples of passing and not passing by long time water and rock interaction.The effective confining pressure which approaches the sample destroying condition has been proposed to analyze the strength characteristics.In order to contrast the study,this paper also presents the conventional triaxial experiments of satiety water sample under the same actual and effective confining pressure values.On basis of the test results,the studied altered rocks have the similar characteristics under high seepage pressure,normal temperature and pressure.The reaction between altered rock and reservoir water is feebleness,which will not affect the rock mass penetrability and mechanics characteristics.