基于Barton剪胀模型的粗糙节理渗流分析

ANALYSIS OF FLUID FLOW THROUGH ROUGH JOINTS BASED ON A SHEAR DILATION MODEL DEVELOPED BY BARTON

为研究粗糙节理在剪切过程中的渗流规律,首先,采用Barton剪胀模型分析节理在剪切过程中的剪胀效应,计算节理在不同剪切位移下的剪胀位移,采用Brown-Scholz(B-S)理论模型分析法向应力作用下的节理闭合变形;通过初始隙宽、法向闭合变形和剪胀位移建立剪切过程中的节理隙宽与法向应力和剪切位移之间的关系,在此基础上得到剪切过程中的节理渗流计算公式;然后,在对节理试件进行渗流试验的基础上,分别采用基于Barton剪胀模型的节理渗流计算公式和Barton经验公式计算通过节理试件的理论渗流流量,并将预测结果与实测值进行比较,比较结果表明,基于Barton剪胀模型的节理渗流计算公式的预测结果与实测值较为一致,而Barton经验公式预测值与实测值偏差较大,从而验证了该公式在计算节理剪切过程中的渗流情况的正确性。

In order to investigate fluid flow through a rough joint during shearing,shear dilation of a rough joint is firstly analyzed by using the shear dilation model developed by Barton,and then dilations under different shear displacements can be calculated.The Brown-Scholz（B-S） theoretical model is employed to compute the closures of joint under different levels of normal stress.The relation of the aperture during shearing with normal stress and shear displacement are established according to the relations among initial aperture,normal closure and shear dilation,on the basis of which a new equation accounting for the volumetric rates through a rough joint during shearing is derived.Then laboratory flow tests on rock joint specimens are carried out;and the new equation derived from the shear dilation model developed by Barton and Barton？s empirical equation are adopted to predict flow rates through joint specimens.Comparisons between theoretical predictions and experimental results are conducted.From the comparisons,it is shown that predictions of the new equation agree well with experimental results while the results of Barton？s empirical equation deviate from experimental results to a large extent,which verifies the validity of the new equation for predicting fluid flow through a rough joint during shearing.