压水试验定量评价注浆效果研究

注浆后岩体渗透性和力学强度是反映岩体注浆效果的重要参数,为定量评价注浆堵水工程效果,以安徽某矿奥灰特大突水抢险注浆堵水工程为例,提出采用钻孔高压压水试验方法,对C53太原组灰岩堵源注浆效果进行定量评价。针对高压压水试验过程中岩体渗透性的剧烈变化特征,提出采用紊流渗透定律计算岩体渗透系数。研究结果表明:C53太原组灰岩注浆后表现出良好的隔水性能,阻水性能呈现出高阻弱渗的特点,渗透性等级属极微~微透水,与注浆前弱~中等透水的渗透性等级对比,渗透性能显著变弱,说明堵源注浆效果良好;可根据临界抗渗强度来评价C53太原组灰岩注浆后抵抗水力劈裂的力学强度,经计算其临界抗渗强度为1.83 MPa/m,依据阻水系数消能试验测试原理,注浆后C53太原组灰岩足以抵抗5.64 MPa奥灰水的劈裂破坏,可以消除煤层底板奥灰突水威胁,能够达到堵源注浆工程目的。

Study on quantitative evaluation of grouting effect by water pressure test

The permeability and mechanical strength of rock mass after grouting is an important parameter to reflect the grouting effect of rock mass.In order to quantitatively evaluate the effect of grouting water plugging project,taking the water plugging project of special large water inrush from Ordovician limestone of a mine in Anhui province as an example,this paper puts forward a method of high pressure borehole water pressure test to quantitatively evaluate the blocking source grouting effect of the Taiyuan formation limestone C53.In view of the drastic change of rock mass permeability during high pressure water pressure test,the permeability coefficient of rock mass is calculated by the turbulent seepage law.The results show that the Taiyuan formation limestone C53 after grouting exhibits a good water resistance performance and the behavior of high water anti-pressure and low permeability.It means that the blocking source grouting has a good effect.The mechanical strength of rock mass to resist hydraulic fracturing can be judged by its critical impermeability strength.The calculated critical impermeability strength of the Taiyuan formation limestone C53 after grouting is 1.83 MPa per meter.Based on the test principle of the energy dissipation test of water resistance coefficient,the Taiyuan formation limestone C53 after grouting is enough to resist the splitting failure of Ordovician limestone water with 5.64 MPa pressure,and it can eliminate the threat of water inrush from Ordovician limestone in the coal seam floor,as well as it can achieve the purpose of the blocking source grouting project.