基于塑性铰理论的导水裂隙带发育高度预判

Prediction of Water Flowing Fracture Zone Height Based on the Plastic Hinge Theory

为更客观和准确地对导水裂隙带发育高度进行预判提供理论支撑。以塑性铰理论为基础结合关键层对岩层移动的控制作用,从理论上阐述了导水裂隙带的形成本质是岩层竖向破断裂隙导气导水能力的形成,并通过数值模拟和工程算例对覆岩结构对导水裂隙带发育的影响进行了分析和验证。研究结果表明:覆岩结构对导水裂隙带的形成和发育有较大影响,处于垮落带范围的关键层破断后若能形成稳定的承载结构,则能有效阻止垮落带向上发展,此时应以关键层所在层位作为垮落带的发育高度;同时,由于导水裂隙带上部岩层下沉空间有限,处于导水裂隙带中上部的关键层在弯曲下沉过程中往往不会发生弯曲破断,从而形成塑性铰结构。此时,可采用塑性铰理论对其竖向贯通裂隙进行分析,确定其导气导水能力,从而对其是否为导水裂隙带的上边界进行判断,进而确定导水裂隙带的发育范围。

In order to provide a theoretical foundation for accurate prediction of water flowing fracture zone height. According to the control effect of key stratum on movement of strata,and based on the plastic hinge theory,this paper theoretically explains the formation mechanism of water flowing fracture zone is the formation of the vertical fracture fissure of stratum,and study the influences of stratum construction on water flowing fracture zone height. The research results show that： the stratum construction has a great influence on the formation of water flowing fracture zone. When the bottom key stratum is in the caving zone and it can form stable bearing structure after its broking,the key stratum can prevent the caving zone development,then the height of caving zone is the position of the bottom key stratum. And because of the sinking space of the stratum in the upper part of water flowing fracture zone is limited,the key stratum in the upper part of water flowing fracture zone will not break completely and can form plastic hinge structure in its process of bending and sinking. Then,the plastic hinge theory could be applied to analyze the vertical fracture of key strata,thus,the water transmitting ability of the key strata can be determined,then the upper boundary of the water flowing fracture zone can be judged. Finally the range of water flowing fracture zone can be estimated.