Zhang Weijie, Wu Fangxiao, Han Chenghao, Li Xinfeng, Peng Ziyu, Ren Qian, Yang Fei, Zhang Danyang
College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China.
Mineral Geological Technology Department, Geophysical Prospecting and Surveying Team of Shandong Bureau of Coal Geology, Jinan 250100, China.
ACS Omega. 2022 Aug 9;7(33):29274-29286. doi: 10.1021/acsomega.2c03450. eCollection 2022 Aug 23.
The deep mining of coal mines in North China faces the serious threat of water inrush from karst aquifers in the coal seam floors, and regional advance grouting technology (RAGT) is an effective means to prevent and control such disasters. However, it is difficult to choose the grouting pressure during the implementation of RAGT, and excessive grouting pressure will lead to the splitting of karst fracture and reduce the grouting effect. In this study, based on the Bernoulli equation, the relationship between the ground grouting pressure and critical grouting pressure during grouting is established. Based on the Hoek-Brown (H-B) strength criterion and a fracture mechanics analysis of hydraulic fracturing, a theoretical equation of the critical grouting pressure for fracture splitting during grouting is obtained. The determination methods of the main parameters, such as the length of the fracture, internal friction angle, and H-B constant of the intact rock and geological strength index, and their effects on the critical grouting pressure, are discussed. The results show that the joint influence of the H-B constant and geological strength index of the intact rock is the key factor influencing the critical grouting pressure. The theoretical research results are applied to the Xujiazhuang limestone grouting reinforcement project of the floor of coal seam 11 in the Zhaoguan coal mine. The critical grouting pressure of the aquifer is determined to be 14.54 MPa, which guides the smooth implementation of the project.
中国北方煤矿深部开采面临着煤层底板岩溶含水层突水的严重威胁，区域超前注浆技术是防治此类灾害的有效手段。然而，在区域超前注浆技术实施过程中，注浆压力难以选择，注浆压力过大将导致岩溶裂隙劈裂，降低注浆效果。本研究基于伯努利方程，建立了注浆过程中地面注浆压力与临界注浆压力的关系。基于霍克-布朗（H-B）强度准则和水力压裂的断裂力学分析，得到了注浆过程中裂隙劈裂临界注浆压力的理论方程。讨论了裂隙长度、内摩擦角、完整岩石的H-B常数和地质强度指标等主要参数的确定方法及其对临界注浆压力的影响。结果表明，完整岩石的H-B常数和地质强度指标的共同影响是影响临界注浆压力的关键因素。理论研究成果应用于赵官煤矿11号煤层底板许家庄灰岩注浆加固工程，确定含水层临界注浆压力为14.54 MPa，指导了工程的顺利实施。
