矿井突水灾害淹没巷道骨料灌注及注浆治理机理试验研究

The salvage and treatment of groundwater inrush inundated tunnels with large cross section encountered several difficulties, such as high water pressure, large flow rate and plugging issues. The treatment method of grouting after aggregate pouring is widely adopted. However, there is a lack of research on the important scientific problems about the settlement and migration of aggregates under dynamic water conditions and the propagation and gelling of grouts inside aggregate deposits. A visualization experimental equipment for aggregate pouring into a pipe under dynamic water conditions will be established to investigate these scientific problems in the present proposal. First of all, the hydrogeological and engineering geological conditions of surrounding rock in groundwater inundated tunnels will be characterized and generalized into a geological model through geological survey. Engineering geological model test will be used to study the compaction characteristics of the aggregate deposit under the condition of high peameable pressure difference. The settlement and migration of aggregate particles in large cross section tunnel will be focused through scale model experiments of aggregate pouring, and the main geological and engineering factors which influence the plugging effect of aggregate deposit will be determined. The propagation and gelling of grouts inside the saturated aggregate deposits after grouting will be studied. The plugging criteria of aggregate deposit will be proposed, and a mathematical model of grouting propagation into aggregate deposit will be deduced. Then, the situation of grouts retention and sealing off effeciency in aggregate deposit will be obtained..The results of the aggregate deposition, the plugging criteria of aggregate deposit and the grout propagation can be used as the scientific foundation for improving the design of grouting and plugging groundwater inrush disasters in inundated tunnels with a large cross section.

矿井突水淹没大断面巷道的灾害治理面临着水压高、流量大、截流难等难点，广泛采用先灌注骨料后注浆的方法治理。但是，目前对于动水条件下骨料在淹没巷道中沉降运移规律以及浆液在骨料堆积体中的扩散与凝固这些科学问题还缺乏研究。本项目将首先通过地质调查方法查明突水淹没巷道围岩的水文地质工程地质条件,概化出地质模型；然后采用室内工程地质模型试验，揭示骨料堆积体在高渗透压差作用下压密特性；重点进行巷道骨料灌注工程地质模拟试验，探究骨料颗粒在淹没巷道中的沉降运移规律，确定影响骨料堆积体封堵效果的主要地质和工程因素；并在骨料堆积体中进行注浆试验，研究饱和骨料堆积体注浆的浆液扩散与凝固规律；建立骨料堆积体封堵判据,推导骨料堆积体中注浆扩散的数学模型，获得浆液在骨料堆积体中的留存与堵水效果。研究获得的骨料灌注的沉积规律、骨料堆积封堵判据和浆液扩散规律为改善大断面淹没巷道注浆堵水工程设计提供科学基础。

围绕矿井突水淹没巷道灌注骨料颗粒的沉降与运移规律、骨料中注浆浆液扩散凝固规律及封堵效果判据等两个关键科学问题，本项目研制了可视化灌注和注浆系统，开展了不同粗糙度和倾角的动水条件下淹没圆型和直墙拱形巷道骨料灌注效果和影响因素研究，获得了动水巷道骨料灌注颗粒沉降和运移规律，揭示了动水巷道骨料灌注封堵机理，建立了巷道骨料堆积体封堵效果判据，揭示了骨料堆积体阻水段注浆浆液扩散和凝固机理、高压渗流作用下骨料堆积体运动破坏规律。（1）正交试验结果表明，各因素对圆型巷道内骨料堵水效果影响程度从大到小依次为动水流速、骨料粒径、孔间距、巷道角度；拱形巷道中，动水流速和骨料粒径是主要因素、粗糙度和巷道倾角是次要因素。（2）圆型巷道中骨料灌注阶段骨料的堆积可以分为沉降堆积、连接堆积和封顶堆积三个阶段；拱形巷道中骨料运移可以分成铺底、堆积、合拢和接顶四个阶段。（3）建立了圆型和拱形巷道灌注骨料的物理机制模型及封堵效果判据。模型可以反映骨料沉积和启动的机理。颗粒粒径越大，滑动摩擦系数越大，起动速度也越大，骨料堆积体越稳定。粗颗粒骨料在灌注过程中的堆积体稳定性要明显比细颗粒的稳定性要好，粗糙度越大，骨料越难以被水流带至下游。（4）骨料堆积体对水流产生阻水消压的效果，水流通过细骨料区域的流速要高于通过粗骨料的流速，粗骨料对水流的降压效果优于细骨料。（5）正交注浆试验表明，各因素对骨料段注浆堵水效果影响主次为水泥-水玻璃双液浆配比、骨料相对密度、骨料级配、动水压力。注浆过程中流体压力表现为整体上升、阶梯上升、凹字型和凸字型四种类型。浆液扩散可以归纳为：O型、T形、H形、壳形四种扩散形态。骨料堆积体内浆液扩散机理包括渗透充填扩散、挤密-渗透扩散、挤密-劈裂扩散。推导了骨料堆积体中浆液扩散的数学模型。研究结果用于山东、云南等地矿山的淹没巷道注浆堵水，为工程设计提供了科学依据。