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岩体粗糙裂隙的细部特征对区域整体渗流分析影响很大,以往渗流分析往往没有考虑粗糙裂隙细部特征以及其对整体渗流分析的影响。提出子单元法来分析岩体粗糙裂隙网络渗流,则可以较好的分析上述影响。子单元法将每一裂隙当成一个单元,裂隙内部则分成若干子单元,裂隙单元的总体水力特征受所有的子单元联合作用控制,而细部水力特征由单一子单元体现。根据单裂隙开度分布统计规律模拟裂隙开度分布,将单裂隙等长分段(子单元),根据模拟开度参数求得裂隙中任一子单元的平均隙宽,进一步推导裂隙的单宽流量公式和子单元结点的水头公式。利用岩体裂隙网络渗流理论,结合粗糙单裂隙等宽流量公式,求得各裂隙结点水头,进一步求得裂隙的单宽流量,进而求得裂隙子单元水头和流速。通过分析可得粗糙裂隙网络渗流与平滑裂隙网络存在明显不同:(1)裂隙网络中任一裂隙单宽流量计算公式不同,粗糙裂隙的等效水力隙宽小于平均隙宽;(2)裂隙内水头分布形式不同,光滑裂隙呈直线状分布,而粗糙裂隙呈阶梯状分布;(3)组成裂隙网络渗流传导矩阵的计算公式不同,粗糙裂隙网络考虑了裂隙细部水力特征对渗流的影响;(4)粗糙裂隙子单元法考虑了裂隙开度分布不均匀对裂隙过流能力的影响,更加合理。本研究可为实际工程提供参考。
The detailed features of the rough fracture of rock mass have a great influence on the overall seepage analysis of the area. In the past, the detailed characteristics of the rough fracture and its influence on the overall seepage analysis are often not considered in the seepage analysis. The sub-element method is proposed to analyze the seepage of the rough fracture network in rock mass, so the above effect can be well analyzed. The subunit method treats each fracture as a unit, and the fracture interior is divided into subunits. The overall hydraulic characteristics of the fracture cell are controlled by the combined action of all subunits, while the detail hydraulic characteristics are represented by a single subunit. According to the statistic rule of the distribution of single crack opening, the distribution of crack opening is simulated, and the average width of any subunit in the crack is calculated according to the parameters of simulated opening, and the single width of the crack is further deduced Flow formula and subunit node head formula. Based on the seepage theory of rock fracture network and the formula of uniform flow with rough single fracture, the head of each fracture is calculated and the single-wide flow of the fracture is obtained. Then the head and velocity of the fracture sub-unit are obtained. The results show that there is a significant difference between the seepage and the smooth fracture network through the analysis of the rough fracture network: (1) The formula of single-wide flow in any fracture in the fracture network is different, the equivalent hydraulic gap width of the rough fracture is smaller than the average gap width; (2) The distribution of the head is different, the smooth cracks are linear distribution, while the rough cracks are distributed in steps. (3) The calculation formulas of the percolation conductive matrix of the fractured network are different. The rough fracture network considers the influence of the detailed hydraulic characteristics of the fractures on the seepage. ) The rough fracture subunit method is more reasonable considering the influence of the uneven distribution of fracture opening on the overcurrent capacity of the fracture. This study can provide reference for practical engineering.