深部煤层开采底板突水地应力控制机理研究

发布时间：2018-04-07 17:40

  本文选题：深部煤层　切入点：底板突水　出处：《煤炭科学研究总院》2015年博士论文

【摘要】：随着我国矿井浅部煤炭资源开采逐渐枯竭,对深部煤炭资源的开采利用势在必行。而随着矿井采掘深度的不断增加,深部煤层带水压开采底板突水的危险性和危害程度更加严重,这除了与煤层底板承受的含水层水压力不断增加的原因之外,还与深部煤层顶、底板围岩所处的高地应力环境有着密不可分的关系。怎样安全有效地把深部煤炭资源从高地应力高承压水开采条件下解放出来,是实现深部煤炭资源安全开采所面临的关键技术难题。在对埋藏深度较浅的煤层实施带水压安全开采的研究工作中,我们通常重点考虑充水水源、充水途径和充水强度三个要素,地应力大小对工作面底板突水的控制作用以及控制机理研究较少,甚至忽略不计,但随着煤层埋深的不断增加,煤层顶、底板围岩所受原岩地应力迅速增大,围岩力学性质、采掘扰动后的力学响应特征、高压水作用下的破断突水机理都会产生有别于浅埋煤层的特殊性质,地应力逐渐成为煤层底板突水的重要控制因素。因此,从理论到工程实际上,系统研究煤层赋存区原岩地应力大小随埋藏深度的变化规律,研究深部煤层围岩所受地应力状态、高地应力对煤层顶底板围岩力学性质的控制机理,高地应力环境中煤层底板岩层在采掘扰动和水压力作用下的损伤破坏特征及其对底板高压水突出的控制作用,进而获得煤层埋藏深度、地应力大小与底板突水危险性评价指标之间的内在关系,是深部煤层开采底板水害形成条件评价与水害防治的关键科学与技术问题,是实现高地应力环境条件下煤层带水压安全开采的重大需求。正是基于上述原因,本论文选择了“深部煤层开采底板突水地应力控制机理研究”作为主要研究内容和研究方向。本论文主要以岩体力学理论为基础,论述了在不同埋深条件下地应力对煤层采掘活动中底板扰动损伤破坏的控制效应,分析了地应力对底板突水的控制机理,提出了地应力与煤层底板扰动损伤破坏深度的量值关系；通过不同围压条件下不同岩性岩石的三轴压缩试验和渗透性测试试验,获得了岩石强度、变形特征和全应力应变过程中渗透性变化规律及量值关系,分析了围压对岩石强度、变形特征、渗透规律的控制效应；通过Flac3D软件的流固耦合数值模拟,分析研究了不同埋深条件下煤层回采后底板围岩应力变化特征、塑性变形破坏特征及分布规律,并对现有突水系数计算公式进行了修正,同时提出了深部煤层带压开采突水危害程度评价预测方法。通过理论分析、实验研究、数值模拟和实测资料统计分析等研究手段,本文得出以下主要结论：煤层围岩垂向地应力随埋藏深度呈递增变化规律,垂向地应力大小与地层埋深基本成正比关系；在其它开采条件和开采参数基本相同的条件下,煤层底板隔水层回采扰动损伤破坏深度随煤层埋深不断增加而呈现增大趋势,煤层围岩地应力的大小与煤层开采后工作面底板破坏深度基本成正比关系,表明地应力对煤层底板岩层损伤破坏深度控制效应明显；论文提出了地应力影响系数的概念及其计算公式：Cd=0.1272△σv+0.8066,并对现有突水系数计算公式进行了修正：Td=P/M·Cd,同时提出了深部煤层带水压安全开采底板突水危害程度评价的单位涌水量——突水系数双因素(q-Td法)评价预测方法。本文研究成果对实现我国高地应力条件下深部煤层带水压安全、有序、高效开采具有重要的理论指导意义和实用价值。
[Abstract]:Based on the theory of rock mechanics , this paper deals with the control mechanism of rock mechanics property of coal seam roof and bottom plate under the action of mining disturbance and water pressure . It is the key technical problem to realize the safety exploitation of coal seam floor .
Through triaxial compression test and permeability test of different lithologic rocks under different confining pressure conditions , the variation law and magnitude relation of rock strength , deformation characteristics and full stress strain are obtained , and the control effect of confining pressure on rock strength , deformation characteristics and infiltration law is analyzed .
Based on the numerical simulation of fluid - solid coupling of Flac3D software , the characteristics , characteristics and distribution of surrounding rock under different burial conditions are analyzed , and the calculation formula of the existing water inrush system is modified . The main conclusions are as follows : the vertical stress of the surrounding rock of the coal seam increases with the buried depth , and the vertical stress magnitude is directly proportional to the burial depth of the formation .
Under the condition that other mining conditions and mining parameters are basically the same , the damage depth of the back - mining disturbance damage of the coal seam floor is increased with the increasing of the buried depth of the coal seam , and the magnitude of the underground stress of the surrounding rock of the coal seam is basically proportional to the depth of failure of the bottom plate after the coal seam mining , and indicates that the underground stress has obvious control effect on the damage of the coal seam floor rock stratum .
In this paper , the concept and the calculating formula of the influence coefficient of floor stress are presented : Cd = 0.272 鈻，

本文编号：1720189