帷幕注浆对露天采坑边坡稳定性影响的有限元数值分析

本文采用ABAQUS软件,通过数值模拟分析了帷幕注浆过程中注浆方式和注浆压力对露天矿坑边坡稳定性的影响。分析表明：单孔和多孔分段注浆时,坡面水平位移随着注浆段埋深的加大而减小,且最大水平位移位置逐渐下移;多孔分段注浆对坡顶沿线水平位移影响差异不大;不同注浆压力下多孔分段注浆时,坡面和坡顶沿线水平位移均随着注浆压力的增加而增大,且最大水平位移位置分别出现在坡顶部分和坡顶沿线中间位置。监测结果表明,此数值分析方法可较好地反映注浆过程中边坡的变形规律。     

桩基空洞质量缺陷注浆补强技术分析

由于水下灌注桩属于地下隐蔽工程,其施工质量受制于多种因素。任何一个影响因素处理不好,都容易发生质量缺陷,其中混凝土不密实导致的桩基空洞是常见的质量缺陷问题。桩基局部空洞形成的原因有多种,其中最主要的原因是地下水流动冲刷造成的。而遇到这种质量缺陷常用而且是较为有效的处理方法是后期补强注浆,但是在岩土工程地基处理方面的注浆技术相比隧道初衬和箱梁预应力结构的注浆技术还尚未成熟,大多数情况下还是受制于注浆配合比和注浆压力等问题。基于此,本文以某桥梁桩基础空洞质量缺陷为研究对象,对补强注浆技术原理和补强施工方案进行了系统分析,并对水泥浆配合比和注浆设备进行了优化,为同类型项目的施工提供了参考依据。     

铁矿立井井筒地面预注浆设计及优化

大贾庄铁矿1号副井井筒地面预注浆工程取得了理想的治水效果,通过对其设计的分析及优化,在保证一定的注浆量和注浆次数的前提下,适当减少钻孔个数至10个或8个。注浆材料主要选择成本低、无污染、堵水率高且耐久性好的单液水泥浆和黏土水泥浆。注浆压力参照《GB50511-2010 煤矿井巷工程施工规范》中的规定,施工过程中终压尽可能地取压力范围的上限。在计算浆液注入量时应根据地质条件和拟注浆液类型将整个注浆段分为若干层段,分别选取最适合参数单独计算,浆液有效扩散距离不应小于10 m。注浆段高的划分需要充分考虑含水层、隔水层和破碎带的位置,并需在施工中根据各钻孔实际揭露的地层情况对注浆段高进行调整。     

复线隧道爆破优化设计与实践

以新风平岭2号隧道复线隧道进口开挖为研究对象,通过在隧道施工爆破过程中对邻近隧道进行现场的振动监测,应用萨道夫斯基经验公式对现场监测数据进行回归分析,控制不同目标、不同间距情况下最大起爆药量,炮眼布置方案等。既有隧道和新开发隧道间采用超前锚杆加固,增强稳定性。通过对振速波形图的分析,找到延时爆破最大振速的段位,降低该段位最大装药量以便降低最大振速,保证邻近隧道振动速度控制在安全范围内,指导后续施工。     

Estimating the groutability of granular soils: a new approach

This paper evaluates different parameters that affect the grouting of soil, and presents a new approach to predict the groutability of granular soil. An accurate prediction of the groutability of granular soils has always been complicated due to the effects of different soil parameters. We know that these parameters are the grain-size of soil and cement-based grouts, the relative density and fine contents of soil, the water/cement ratio of grout mixture and grouting pressure, which directly affect the groutability of soil media. However, the relative density, fine contents of soil, the water/cement ratio, and grouting pressure are seldom considered as the prediction of groutability. In order to study the effects of the parameters on groutability, an alternative empirical formula to estimate the groutability of granular soils is presented in this paper and supported by experimental results obtained from the grouted sand samples prepared with various relative densities. The newly developed approach will help for the more accurate prediction of the groutability in granular soils and may also be used to provide first-hand information about the groutability of soils.     

水泥混凝土路面板底压浆技术应用

分析水泥混凝土路面破板起因,根据＂防重于治＂的原则,针对路面板块脱空或沉陷进行板底压浆,充实板底,均匀传递荷载,从而在大大延长水泥混凝土路面的使用寿命,改善行车质量,降低养护成本,具有较好的社会经济效益和推广前景。     

Basic mechanism of elastic jacking and impact of fracture aperture change on grout spread,transmissivity and penetrability

One of the most important parameters in the grouting of rock fractures is the applied pressure. This produces the driving force on the Bingham group material that causes it to penetrate the fracture. However, deciding the optimum pumping pressure is challenging. Using too high a pressure not only causes the grout to spread beyond the desired area, but, if it exceeds the minimum in situ stress in the rock mass, may also cause jacking of the fractures. This may lead to uncontrolled uplift. With a lower grout pressure, this “ultimate state” (jacking) can be avoided, although the pressurized grout still may induce smaller elastic deformations during pumping, and these may become irreversible when the grout has hardened. In previous studies, various theoretical approaches to distinguish the onset of these elastic and non-elastic deformations have been described and evaluated. However, the merits and disadvantages of theoretical approaches in general have been questionable. In the current study, the basic mechanism of elastic jacking is described, and its negative consequences are analyzed and quantified. These are the prolongation of grouting time, and the reduction in sealing efficiency. The role of an increased grouting pressure is evaluated by considering its positive effect in improving the penetrability and comparing this with the potential negative consequences. Case studies from two projects (the THX and Citybanan projects) are studied to examine the efficiency of the work that was carried out on site. The results indicate a high-applied pressure can have negative effect on the grouting procedure, and that this effect is significant in fractures situated in weak rock at shallow depth. It is concluded that unwanted fracture deformations and their negative consequences can be eliminated by defining appropriate stop criteria in advance of grouting, and confirming their suitability during pumping by the use of theoretical approach presented here. In general, this will allow the use of lower pump pressure and allow better control of the grout spread.     

灌浆方案的模糊优化及其工程应用

建立了灌浆方案优化的模糊综合评判模型，运用模糊综合评判方法对待选灌浆方案进行了优化，在工程实际中具有广泛的适用性和有效性。     

多种复杂地质条件下注浆加固技术研究

针对裂隙蚀变带大而宽、涌水量大、岩体破碎等多种复杂地质条件影响下的井巷掘进问题,以西石门铁矿北区深部开拓工程为例,在分析注浆工艺特点的基础上,考虑矿山地质条件及施工条件,提出了充填、渗透、劈裂联合注浆的整体方案,较好地满足了复杂地质条件下的稳固施工需要,适应了不同类型的施工需求,保证了深部开拓工程的顺利实施。     

巷道注浆钻孔设计关键参数确定方法探讨

针对煤矿注浆钻孔设计存在随意性强、注浆效果差的问题,以赵庄煤业33072巷注浆加固为工程背景,采用钻孔窥视方法确定了深层和浅层钻孔的深度,采用不同注浆压力下浆液扩散半径试验确定了钻孔间排距和最小注浆压力,浅层和深层钻孔深度分别确定为3 m和10 m;浅层钻孔排距2 m,间距1.1 m,最低注浆压力6 MPa,深层钻孔排距4 m,间距1.5 m,最低注浆压力8 MPa.注浆后钻孔窥视结果说明,浆液扩散效果良好,未发现未被填充的裂隙。