在坚硬厚煤层放顶煤开采中顶煤的水力致裂软化、隧道等地下硐室在地下水作用下围岩和衬砌的破坏过程、边坡工程的稳定性、水电站大坝的裂缝在水压诱导下的破坏过程、矿井的保水开采、岩体地热能的开发、石油开采等大量岩石工程中都涉及到工程岩体在水压力驱动作用下，岩体中裂缝的起裂和扩展，导致岩体的宏细观结构破坏，岩体的渗透性也随之发生改变，弱化岩体的强度。因此有必要对诸多岩体工程的共同的基础性问题开展研究。本文以裂隙岩体的水压裂缝为研究对象，在参与导师项目煤岩水压裂缝扩展行为特性试验研究的基础上，分析了水压裂缝扩张的压力参数与扩展过程特性，并对渗透压力作用下裂隙岩体细观结构破坏进行了初步的分析。 运用线弹性断裂力学和数值模拟分析了圆孔孔壁水压裂缝扩张的压力参数及其与地应力场及孔壁围岩力学特性的关系；分析了水压裂缝扩展过程的阶段性特点。并分析了岩石的非均质性对水压裂缝扩张压力参数和扩展形态的影响。 为了控制水压裂缝的扩展形态，运用弹脆性蠕变损伤理论对水压裂缝的损伤断裂扩展过程进行了分析；得出了圆孔水压致裂孔壁断裂潜伏阶段孔壁断裂起始时间 ，得出了水压裂缝发展速度方程和断裂发展方程。 在前人研究基础上，运用断裂力学分析了渗透压力作用下裂隙岩体裂隙扩展的最小水压力和裂隙的扩展长度。从能量耗散损伤的角度分析了岩体细观结构破坏与宏观力学性能弱化的关系。建立了考虑预先弱化特性的裂隙岩体本构关系的细观统计损伤模型。 最后将实验和理论分析结果应用于现场坚硬煤体水力致裂软化技术，实践证明，水压裂缝的破裂与扩展改造了岩体整体性结构和弱化了其力学特性。

The macroscopical and mesoscopic structure of rock mass is destroyed due to the spliting and expanding of crack in rock mass under the driving of hydraulic pressure in much rock engineering, such as hydraulic fracturing softing for top coal in the caving of hard thick coal seam, the destroying process of sorrounding rock in underground engineering under the effect of underground water, the stability of slope projects, mining of mine on the basis of protecting water, petroleum exploiting and so on. The penetrability of rock mass also changes for the sake of it. The strength of rock mass is weaken. Therefore, research on common basic problem of much rock engineering needs to proceed. In this paper, hydraulic crack of fissured rock is studying object. The research of this paper was executed on the basis of participating in experimental study on the character of expanding behavior of hydraulic crack for coal rock which is my instructor’s item. The pressure parameters and process character of hydraulic crack’s expanding were analyzed. Preparatory analysis was proceeded for mesoscopic destruction of fissured rock under penetrating water pressure. Pressure parameters of hole wall hydraulic crack’s expanding and the relation between ground stress field and mechanics property of rock mass with it were analyzed with linear elasticity fracture mechanics and numerical simulation. The phase character of expanding process for hydraulic crack was analyzed. The effect of rock’s non-uniformity to pressure parameters and expanding configuration of hydraulic crack were analyzed. In order to controlling the expanding configuration of hydraulic crack, the damage and fracture expanding process of hydraulic crack was studied with the theory of elasto-brittle creep damage. The starting time of circinal hole wall rupture in the latency phase of hydraulic fracture was attained. At the same time, the expanding velocity equation and fracture progress equation of hydraulic crack were also attained. On the basis of former people’s study, the least hydraulic pressure and length of crack expanding in fissured rock under the effect of penetrating hydraulic pressure were analyzed with fracture mechanics. The relation between mesoscopic destruction of rock mass with the weakening of macrocosmic mechanics property was analyzed by the way of energy dissipating damage. Constitutive relation with the model of mesoscopic statistical damage of fissured rock which considered the beforehand weakening character of rock was established. At last, the result of experimental and theoretical analysis was applied to locale softening technology of hydraulic fracture for hard coal mass. Practice showed that the rupture and expanding of hydraulic crack altered the whole structure of rock mass, and that weaken the mechanics property of it.