奥陶系灰岩顶部劈裂注浆裂隙起裂机制试验研究  

Experimental study on fracture initiation mechanism of split grouting fissure in Ordovician limestone top

作　　者：柳昭星 LIU Zhaoxing(Xi'an Research Institute,China Coal Technology and Engineering Group,Xi'an,Shaanxi 710054,China;Shaanxi Key Laboratory of Prevention and Control Technology for Coal Mine Water Hazard,Xi'an,Shaanxi 710077,China)

机构地区：[1]中煤科工西安研究院(集团)有限公司,陕西西安710054 [2]陕西省煤矿水害防治技术重点实验室,陕西西安710077

出　　处：《采矿与安全工程学报》2023年第1期204-214,共11页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(52104240);陕西省自然科学基金项目(2022JQ-320)。

摘　　要：劈裂注浆是底板水害超前区域注浆治理的最后阶段,是决定工程效果的关键环节,但由于对裂隙起裂机制认识不清,导致对该阶段浆液水灰比、注浆压力等参数选择和控制缺乏理论依据。针对上述问题,基于真三轴压裂试验平台,考虑浆液水灰比、地应力水平、裂隙与最大主应力夹角等因素,开展了劈裂注浆物理相似材料模拟试验研究,其中相似材料配比通过标定试验获得。试验结果表明:试样起裂压力随着水灰比增大而降低;在相同地应力水平和浆液水灰比条件下,试样起裂压力随着裂隙与最大主应力夹角的增加而增大;在固定最大主应力和中间主应力、浆液水灰比和裂隙与最大主应力夹角的情况下,起裂压力和二次劈裂压力均随着最小主应力的降低而降低,但二次劈裂压力降低幅度要高于起裂压力降低幅度;在相同工况下,二次劈裂压力大于起裂压力,并且二者的差值随着最小主应力的降低而降低。研究结果有助于底板水害超前区域治理劈裂注浆阶段参数选取和控制。Split grouting is the last stage of grouting treatment in the area ahead of the floor which has water damage,and it is the key link to determining the engineering effect.However,due to the unclear crack initiation mechanism,there is no theoretical basis for the selection and control of parameters such as water-cement ratio and grouting pressure in this stage.Given the above problems and based on the true triaxial fracturing test platform,the physical similar material simulation test of split grouting was carried out taking into account such factors as slurry water-cement ratio,in-situ stress level,and the angle between fracture and maximum principal stress,in which the similar material ratio was obtained through the calibration test.The test results have shown that the crack initiation pressure decreased with the increase of the water-cement ratio;Under the same in-situ stress level and water-cement ratio of grout,the crack initiation pressure increased with the increase of the angle between crack and the maximum principal stress;When the maximum principal stress and the intermediate principal stress were fixed,the water-cement ratio and the angle between the crack and the maximum principal stress were also fixed,the fracture initiation pressure and the secondary splitting pressure decreased with the decrease of the minimum principal stress,but the reduction of the secondary splitting pressure was higher than that of the fracture initiation pressure;Under the same working condition,the secondary splitting pressure was greater than the fracture initiation pressure,and the difference between the two pressures decreased with the decrease of the minimum principal stress.The research results are helpful to the selection and control of parameters in the stage of splitting grouting for advanced area control of floor water damage.

关 键 词：底板超前区域治理 劈裂注浆 裂隙起裂机制 相似材料模拟 

分 类 号：TU452[建筑科学—岩土工程]