CAJ | 학술논문

在理论分析水压致裂起裂机理和起裂方向的基础上,应用煤岩损伤破裂过程渗流-应力耦合分析系统,对5种不同地应力条件下的本煤层水压致裂过程进行模拟,得到了煤体的起裂方向、起裂压力和扩展压力.研究发现:侧压系数λ＜1时,煤体基本沿垂直方向起裂,起裂压力和扩展压力呈逐步增长的趋势;λ＞1 时,煤体的起裂方向为水平,起裂压力和扩展压力表现出平缓降低的趋势;在λ=1时,运用3种屈服准则进行了对比分析,得到了不同判别准则下的最小起裂水压.通过对λ=1.2时的受力状态进行深入分析,提出了压裂增透范围为宏观裂隙区、微裂隙贯通区、微裂隙产生区(受拉区)和原生裂隙扰动区(压应力恢复区)之和;利用数值图像处理得到的增透面积增长趋势符合二次函数的关系.
재이론분석수압치렬기렬궤리화기렬방향적기출상,응용매암손상파렬과정삼류-응력우합분석계통,대5충불동지응력조건하적본매층수압치렬과정진행모의,득도료매체적기렬방향、기렬압력화확전압력.연구발현:측압계수λ＜1시,매체기본연수직방향기렬,기렬압력화확전압력정축보증장적추세;λ＞1 시,매체적기렬방향위수평,기렬압력화확전압력표현출평완강저적추세;재λ=1시,운용3충굴복준칙진행료대비분석,득도료불동판별준칙하적최소기렬수압.통과대λ=1.2시적수력상태진행심입분석,제출료압렬증투범위위굉관렬극구、미렬극관통구、미렬극산생구(수랍구)화원생렬극우동구(압응력회복구)지화;이용수치도상처리득도적증투면적증장추세부합이차함수적관계.
Based on the theoretical analysis of crack initiation mechanism and crack direction of hy-draulic fracturing, the hydraulic fracturing process of coal seam under five different in-situ stress situa-tions has been simulated by using the seepage-stress coupling analysis system of coal and/or rock dam-age & fracture process, and hence, the crack initiation direction, initial pressure and expansion pressure have been obtained. Studies have found that, the crack direction is vertical, with the initial pressure as well as the expansion pressure presenting as gradual increasing trend when the lateral pressure coeffi-cientλ＜1. When the lateral pressure coefficientλ＞1, the crack direction is horizontal, with the initial pressure and the expansion pressure presenting as gradually decreasing trend. When the lateral pressure coefficientλ=1, by carrying out three different kinds of yield criterion contrastive analysis, the minimum initial pressure are respectively obtained under the different kinds of yield criterion. Through the further stress analysis, i.e., when coefficientλ=1.2, studies have proposed that the antireflection range of hy-draulic fracturing is the summation of macro-crack zone, micro-crack crossing zone, micro-crack generation zone (tension zone) and native crack disturbed zone (pressure recovery zone); the growth trend of anti-reflection area which has been obtained by digital image processing ac-cords with quadratic function.