【作者】 温帅；

【导师】 汪家林；

【作者基本信息】 成都理工大学 ， 地质工程， 2010， 硕士

【摘要】 大岗山水电站为混凝土双曲拱坝,最大坝高210.0m,在拱坝基础及两岸传力部位分布有较多性状较差的辉绿岩脉,影响建筑物的稳定性。为了有效解决辉绿岩脉地质缺陷这一技术难题,在总结前期试验成果和分析岩脉特征的基础上,选择代表性试验区,采用高压水泥–化学复合灌浆技术,对辉绿岩脉的灌浆加固处理开展了灌浆方案、工艺流程、加固效果和加固机理等方面的研究。试验中对试验区岩体进行水泥灌浆后再进行化学复合灌浆,水泥浆液采用普通硅酸盐水泥,化学浆液采用固结性能良好的CW1环氧树脂,灌浆后试验区岩体的整体性、连续性、坚固性均得到提高,灌浆效果显著。本文主要结论如下:(1)采用高压水泥-化学复合灌浆技术是必要的。辉绿岩脉整体呈陡倾、微细裂隙发育、裂隙开度相对较小,常规条件下水泥浆液难以灌入0.2mm以下宽度的裂隙,为了充分利用化学浆液的真溶液等特点充填、胶结水泥浆液难以达到的部位,采用高压水泥-化学复合灌浆方案,即首先进行高压水泥灌浆,其结束后基础再进化学复合灌浆,研究复合灌浆后的加固效果。(2)采用复合灌浆对辉绿岩脉进行处理是经济的、可行的。经统计分析,水泥浆液在辉绿岩脉中的单位注入量约为在花岗岩中的1/6;在岩体均一性相对较好的基础上进行化学灌浆,既能保证质量又节省灌浆材料,环氧浆液能够充填到宽度0.01mm的极微细裂隙中,且胶结密实。当辉绿岩脉与周围花岗岩的单位注入量差别较大时,依靠注入量很难清楚判断灌浆效果,应结合其他手段进行灌浆效果检测,如声波或钻孔弹模测试手段。(3)复合灌浆施工工艺、参数合理,可指导施工。试验中水泥灌浆孔间距2.0 m,化学灌浆孔间距1.4 m,均分三序施工。水泥灌浆最大目标压力5.0 MPa,主要采用“孔口封闭、自上而下、分段循环”灌浆工艺,实际工程应用中可增加5:1、3:1两级水灰比,提高对微细裂隙的有效灌入;化学灌浆在水泥灌浆基础上复合,最大目标压力4.4 MPa,采用“分段阻塞、纯压式”灌浆工艺,同时采用“压力下结束”和“定量灌注结束”双控标准结束灌浆。(4)试验区岩体完整性、连续性和坚固性提高。化学复合灌浆后两种岩性的单孔波速基本相同(花岗岩段为5184m/s,较灌浆前提高13.4%;辉绿岩段为5153m/s,较灌浆前提高40.9%),跨孔波速为4876m/s,较灌浆前提高14.4%,透水率均小于1Lu,岩体完整性提高;变形模量在15.35~16.60GPa范围内,约为灌浆前的1倍,环氧浆液能够充填到0.01mm的极微细裂隙中,且胶结密实,岩体连续性大幅提高;取芯平均干抗拉强度达到5MPa以上,平均干抗压强度可达75~90MPa,甚至更高,抗剪断系数提高,岩体坚固性增强。(5)复合灌浆加固岩体的实质可归纳为:复合灌浆后裂隙被充填、胶结,其端部应力集中被降低或消除,受力后破坏由压剪状态转变为纯剪,抗扩展、破坏能力提高;试验区岩体在灌浆后不利结构面组合得到改善,形成连续均匀的结构体,部分地应力得到恢复,抗变形能力增大,故灌浆后试验区岩体强度和刚度均得到提高,达到了加固岩体的效果。更多还原

【Abstract】 Dagangshan hydropower station is a 210.0m concrete hyperbolic arch dam, there are more diabase dikes of poor distribution in the dam foundation and two sides that is the force transfer part, and affect the stability of the building. In order to effectively solve the problem of geological defects in diabase dikes, base on the pre-test results and the dikes characteristics, and select representative test area, taking the techniques of high-press cement and chemical grouting, and by the experiment studying the grouting plan、technological process、reinforcement effect、reinforcement mechanism and so on. During the experiment, in the rock-mass of test area, the high pressure cement grouting has been adopted firstly and then the chemical compound grouting is carried out. The material of cement slurry is ordinary portland cement,and the material of chemical grouting is epoxy resin with super consolidation performance,which belongs to the CW series. After the compound grouting, the entirety、continuity and sturdiness of rock mass in the test area are improved significantly, and the grouting effects are good.The main conclusions of the paper are as follows:(1) The technique of high-pressure cement and chemical compound grouting is necessary. Diabase overall was steep, which micro-cracks are developed and fracture aperture is small relatively, cement grout poured into the crack width of 0.2mm and it’s below is difficult in the normal condition. In order to make full use of the true solution of chemical grout fill and cement grout the rock-mass part which the cement grout can’t fill, taking the compound grouting plan that the high pressure cement grouting has been adopted firstly and then the chemical compound grouting is carried out, and study the reinforcement effect after the compound grouting.(2) Taking compound grouting reinforced the diabase is economical and feasible. Viewed from the different lithologies, the unit slug size of cement grout in diabase dikes is about 1/6 than in the granite, when the uniformity of rock-mass is relatively superior, taking chemical grouting not only ensure quality but also save materials, and epoxy grout can fill to the very fine cracks which is 0.01mm, and dense cementation. When the unit slug size is large difference between the diabase and granite which around the diabase, it is difficult to determine grouting effect for depending on the amount, should be combined with other means of detection of grouting effect, such as sonic testing or borehole elastic modulus testing methods.(3) The construction technology and the parameters of compound grouting are reasonable, which can directly guide the foundation treatment construction. In test, the distance between holes of cement grouting is 2.0m, and the distance between holes of chemical grouting is 1.4m, both constructions of them are divided into three sequences. The maximum target pressure of cement grouting is 5.0MPa, and the" hole-top-enclosed, top-down, sub-cycle" grouting technology is mainly used. For practical engineering application, should be increased both 5:1and 3:1 water-cement ratio and the effective injection of micro-cracks will be improved.The maximum target pressure of chemical grouting is 4.4MPa, and the" piecewise- obstruction, pure-compression style" grouting technology is mainly used, meanwhile, both "end under pressure" and " end of the quantitative perfusion " are used for grouting end standard .(4)The entirety、continuity and sturdiness of rock mass in the test area are improved significantly. After the compound grouting, sonic wave in diabase can reach 5184m/s, which increase 40.9%, in the granite can reach 5153m/s, which increase 13.4%, their cross-hole sonic can reach 4876m/s, which increase 14.4%, and the average pervious rate less than 1Lu, the rock-mass entirety is improved. The deformation modulus is in the range of 15.35–16.60GPa, and grout can fill to the very fine cracks which is 0.01mm, and dense cementation, the rock-mass continuity is improved. The average dry tensile strength of core is 5MPa, the average dry compressive strength is up to 75~90MPa or even higher, and the anti-shear is increased, the rock-mass sturdiness is improved.(5)The essence of the cement-chemical compound grouting for reinforcing the rock mass can be summarized as follows: after consolidation grouting, It is the fine filling and cementation of micro-cracks that reduce or eliminate the stress concentration on their ends intensively,and after force the failure mode from the compression - shear mode into pure-shear mode and its strength are enhanced. Meanwhile, the structural plane of rock mass and its disadvantage combination are improved, and form continuous and uniform structural body, and then partially restored stress and the anti deformation capacity is improved, so the strength and stiffness of rock-mass are increased after compound grouting, achieve the desired results.更多还原