Y型通风沿空留巷巷道围岩活动规律研究

On the regularity of the surrounding rock displacement along the roadway of the gob-side entry in the Y-shaped ventilation manner

为掌握沿空留巷围岩活动规律,以谢桥矿12418工作面轨道顺槽为工程背景,采用多点位移计及钻孔窥视仪等设备进行实测研究,并结合数值模拟对其进行分析。结果表明：沿空留巷巷道表面围岩变形具有典型的近场效应,留巷前距工作面60 m以外的巷道基本无表面位移,随工作面的推进,巷道表面位移逐渐增大,距工作面10~15 m范围内,表面位移变化速率显著增加,留巷后巷道表面位移与留巷前变形趋势类似,但表面位移量较留巷前有明显增加;从顶板钻孔窥视结果可以看出,留巷前仅在孔深2 m处发育单一离层裂隙,留巷后在孔深1.2 m、2.4 m、3.8 m和5.3 m处发育多层离层裂隙,且随滞后工作面距离增加裂隙逐渐增大;尾巷充填体应力在充填材料固结后逐渐升高,并一直维持较高应力状态,因此,巷旁充填体既要确保有一定的强度和刚度,又要有一定的适应变形能力。

The present article is aimed at introducing its study findings on the regularity of the surrounding rock displacement along the roadway of the gob-side in hoping to disclose the effect of the activity regularity of the surrounding rock displacement on the gob side entry maintenance.It is just for this purpose that we have conducted a series of field tests by using a multipoint-displacement instrument and a hole-boring camera based on the 12418 working face gateway in the Xieqiao coal mine.At the same time,we have also made the related analyses of the internal activity regularities of the rocks via a numerical simulation model in the actual coal mining spot.The results of our study help us to disclose the following results：（1） The deformed or damaged surface of the surrounding rocks tends to indicate typically approximate effects on the gob side entrance,which implies that there doesn＇ t seem to be any obvious surface displacement beyond 60 m when the interface between the front of the gob-side entry retaining part and the working face.There can hardly be found any gradual surface displacement increase with the gradual advancement of the working face.Therefore,in most cases,the surface displacement changing rate has been usually kept within a limit of 10 m to 15 m from the working face.However,with the obvious increase of the surface displacement,there may appear bigger and bigger front gob side entry retaining force,which tends to reveal a similar displacement damage trend with the surface of the back gob side.（2） Seen from the images of the hole-boring roof,we can find some singe bed displacement or separation at the depth of 2 m in the front of the gob side entry,which has been followed by a multi-layer bed crack at the depth of 1.2 m,2.4 m,3.8 m and 5.3 m.The said crack may in turn be increasing with the distance moving away from the backside of the working face.（3） What is more,the surrounding rock at the back of the gob-side entry may have been found with poor stability of its props,which can then be becoming hard to be controlled,and even turn to be unexpectedly instable and lead eventually to collapse.（4） There would be a tendency for the backfill side of the tail roadway to migrate more or less due to the high surrounding stress,which tends to increase because the consolidation measures have been taken to prevent from the stress of the backfill in the tail roadway later.Therefore,it proves it necessary to take measures needed to strengthen the backfill support beside the roadway so as to increase the rigidity and the capacity of the gob side.entry to prevent the likely deformation.Thus,it can be seen that the given research should be taken as a guide to the further research for the future design of gob side entry maintenance for the safety production of the similar working faces.