湖南镇大坝12^#坝段帷幕稳定性分析

湖南镇大坝１２＃坝段挡水运行不久，曾发生帷幕后部渗漏量骤增、扬压力超限异常现象，经灌浆处理帷幕后部渗流恢复正常运行状态。本文依据长系列渗流观测资料，对１２＃坝段帷幕的稳定性进行分析研究     

裂隙弱面注浆加固后的抗剪切特性及破坏特征

基于天然岩体内原生裂隙易造成工程围岩失稳的背景,采用自制砂浆体裂隙弱面模拟均质性较好岩体内部裂隙弱面,并以注浆加固后的裂隙弱面为研究对象,开展其抗剪切特性和破坏特征的研究。研究结果表明：法向压应力增大时提升了裂隙弱面滑动的阻力,导致注浆加固后的裂隙弱面抗剪切能力增强,表现为抗剪切强度增大；注浆材料强度、材料粘黏力的增大也可促使裂隙弱面的抗剪切能力增强,其增长趋势不受砂浆体强度和法向压应力大小的影响,但会受注浆材料粘黏力的影响；注浆加固后裂隙弱面受剪切力作用时,剪切破坏面多出现在弱面的两侧,且常以弱面滑移破坏、注浆体破断、砂浆体剪切断裂的形式存在,其中注浆体破断是材料内部晶体错动断裂的宏观表现。研究结果不仅为改善岩体内部裂隙弱面注浆加固工艺提供了一定的理论参考,也为注浆材料的研发提供了思路。     

尾矿库坝基防渗帷幕注浆工艺适用性与改进研究

国内有色金属矿山尾矿库多存在库区渗漏和场地污染问题,很多防渗工程中采用了帷幕注浆技术。但是限于场地条件差异,对于很多薄覆盖层下风化基岩注浆施工而言,存在浆液扩散难、防渗效果差等问题。究其根本原因,除了注浆材料和浆液类型的适用性以外,注浆工艺与地质条件的匹配度是重要影响因素之一。研究结合某尾矿库坝基防渗工程,对常规注浆工艺的适用性进行了试验验证。针对常规工艺存在的注浆压力难增大、易发生地面冒浆和孔内固管事故问题,优化改进形成“孔内封闭局部循环”注浆工艺及装置。新工艺经过现场实际验证,适用性优于常规工艺,可以有效提高注浆质量、减少地面冒浆和孔内事故,适于在类似地质条件的帷幕注浆项目中推广应用。     

北洺河铁矿断层破碎带区域巷道掘支施工技术

北洺河铁矿矿区东部MB4勘探线到MB5+25勘探线之间存在一条较大的F3断层,该断层成因复杂,由起初的正断层经构造运动改造为具有逆冲性质的平移断层,断层为一产状为NW307°∠65°,垂直滑距约8.9 m,水平滑距约17 m的压扭性断层。伴随该断层的主断面分布一条宽约10 m的破碎带,该带宽度较稳定,但破碎带中岩石的破碎程度稍有差异,在与其他优势构造方向交汇处,岩石破碎严重,受地下水活动影响,岩石风化严重,工程地质条件差。北洺河铁矿在-200 m水平13#联巷掘进至F3断层破碎带区域时,发生了大面积塌方。北洺河铁矿对塌方空区范围进行探测后,采用混凝土对塌方空区进行浇筑充填;待混凝土凝固后,从上部施工注浆孔,对断层区域破碎岩体及塌方松散体采用渗透注浆的方式进行胶结加固,后采用U型钢支架与超前锚杆护顶的联合支护方式顺利完成了13#联巷的安全贯通。     

Theoretical and experimental study on the rheological properties of WIS grout and the dispersion and sealing mechanism

Recently a new grout material called water inflow sealing (WIS) was invented for sealing water inflow in tunneling and underground constructions. In this study, a special experimental method called intubated counter grouting (ICG) was proposed to investigate the influence of water dispersion on the rheological properties of the grout during the grouting process, and to testify the sealing performance of the grout, such as instant gelling ability (IGA) and anti-dispersion ability (ADA). In the experiment, dispersion was restricted in the downstream of the channel with a high turbulence intensity. The influences of ADA and IGA were therefore decoupled and evaluated separately. Experimental results revealed two distinctive sealing mechanisms of WIS. For a low initial velocity of water, WIS turned the shear flow of water into an overall movement of a plug by absorbing water into the particles. For a high initial velocity and the situation that the particles reached the outlet before sufficiently expanding, WIS modified the rheology of the water in the channel and reduced its velocity till the static state. The distinctive feature of WIS brings a reformation on the sealing mechanism and provides an effective way to control water inflow with high pressure and velocity.