斜井井筒风积沙段拱部轴向开裂规律研究与治理技术

Law Research and Treatment Technology of Axial Cracking of Arch of Wind-sand Section of Inclined Shaft

朱家峁煤矿首次发现主、副斜井井筒拱顶轴向开裂后,即开始进行原因分析和治理的多方案的制定、选择、论证。提出的治理方案主要有地面旋喷注浆加固、深层搅拌桩法、斜井井筒两帮壁后土层压力帷幕注浆法。通过分析井筒受力状态,提出造成井筒拱顶轴向开裂且持续发展的最主要原因是斜井井筒左右两帮土层对井筒的水平支撑反力不足这一观点,经论证后确定了井筒的拱顶轴向开裂段治理技术,对井筒左右两侧土层注浆加固,以提高拱形井壁结构左右两侧土层的水平支撑反力,同时减少左右两侧土层沉降的治理方案。注浆加固后,井筒周围的土层虽然仍会有塑性变形,但变形速率极为缓慢,而且在注浆加固期间挤密加固了地层,一定程度地减小已发生的拱顶裂缝、拱肩裂缝的宽度,并且对井筒开裂段井壁加强支护,从而缓解井壁破裂危险程度。截至目前,朱家峁煤矿3条井筒拱顶开裂段理后稳定,井筒拱顶开裂未见扩大现象。

After the axial crack of main and auxiliary inclined shaft vault was found for the first time in Zhujiamao Coal Mine,the cause analysis and the formulation,selection and demonstration of multiple plans for treatment were started.The proposed treatment schemes mainly include ground rotary jet grouting reinforcement,deep mixing pile method and soil pressure curtain grouting method behind the two sides of in⁃clined shaft.By analyzing the stress state of the shaft,it is proposed that the main reason for the axial crack of the shaft arch and its sustainable development is the insufficient horizontal supporting reaction of the left and right side soil layers of the inclined shaft.After demonstration,it is determined that the axial crack sec⁃tion of the shaft arch should be treated by grouting reinforcement of the left and right side soil layers of the shaft to improve the horizontal supporting reaction of the left and right side soil layers of the arch shaft struc⁃ture,which.Reduces the soil subsidence on both sides of the treatment scheme at the same time.After grout⁃ing reinforcement,the soil layer around the shaft will still have plastic deformation,but the deformation rate is very slow.Moreover,during the grouting reinforcement,the stratum is strengthened by compaction,which reduces the width of the vault crack and spinner crack to a certain extent,and strengthens the support of the shaft wall in the cracked section of the shaft,so as to alleviate the risk degree of shaft wall fracture.Up to now,the crack section of the third shaft vault of Zhujiamao Coal Mine is stable,and the crack of the shaft vault has not expanded.