保浆袋囊钻孔控制注浆动水快速截流机制数值模拟

Numerical simulations of the rapid interception mechanisms by the borehole-controlled grouting with grout-conserving bags under flowing water

为了更加细微和形象地刻画保浆袋囊钻孔控制注浆动水快速截流局部和整体发展过程,按照等流速原理构建了巷道进水口在给定水头边界条件下CFD-DEM流固耦合数学模型,在2000 m^(3)/h和20000 m^(3)/h突水水量等流速条件下,分别对有无保浆袋囊工况22 mm粒径骨料灌注堆积阻水体建造过程进行了数值模拟。结果表明:(1)低流速条件骨料都能堆积接顶,高流速条件骨料都只能堆积至巷高的3/4,主要差异是有袋囊工况阻水体堆积至相同高度所需时长都更短且都具有高阻弱渗阻水性能。(2)高流速条件阻水体不能局部接顶情况下,单纯增大骨料粒径仍然难以局部接顶,但是单纯增加骨料灌注速度可以局部快速接顶。(3)分析有无袋囊工况阻水体建造结果差异原因,得到保浆袋囊钻孔控制注浆动水快速截流机制其一是袋囊自身快速充填了部分阻水体空间,相当于提前完成了部分骨料铺底和充填阶段;其二是阻水体高阻弱渗的阻水性能,可以减少堵水后期阻水段快速升压阻水体突破再造次数,同时有利于补充注浆阶段浆液快速凝结。

Grout-conserving bags.To characterize the local and overall development processes of the rapid interception more subtly and vividly,this study built a CFD-DEM fluid-solid coupling mathematical model of the roadway inlet under the given water head boundary according to the principle of a constant velocity.Then,given constant velocities of water inrush volumes of 2000 m^(3)/h and 20000 m^(3)/h,this study numerically simulated the construction process of water-blocking bodies by pouring and stacking aggregates with a grain size of 22 mm under the operating conditions with or without grout-conserving bags.The results show that:(1)Under both operating conditions,aggregates can accumulate to the roadway roof in the case of the low flow velocity but can accumulate only to 3/4 of the roadway height in the case of the high flow velocity.The main differences were that when grout-conserving bags were applied,water-blocking bodies were constructed to the same height in a shorter time while exhibiting higher blocking and lower water permeability;(2)In the case of the high flow velocity,aggregates still cannot accumulate to the roadway roof locally by simply increasing the grain size of aggregates but can swiftly accumulate to the roadway roof locally by simply increasing the pouring speed of aggregates;(3)As shown by the analytical results of the reasons for the differences mentioned above,there are two mechanisms of the rapid interception under flowing water by the borehole-controlled grouting with grout-conserving bags.One is that the bags themselves quickly formed part of the water-blocking body space.In other words,aggregates were put at the roadway bottom and filled in the roadway locally in advance.The other mechanism is that the high resistance and low permeability of the water-blocking bodies can reduce the reconstruction number of water-block-ing bodies after being broken through in the later water-blocking stage as a result of the rapid pressure rise in the water-blocking section.Furthermore,these water-blocking performances of water-blocking bodies are conducive to the rapid coagulation of grout in the supplementary grouting stage.