【作者】 彭永良；

【导师】 胡卸文；

【作者基本信息】 西南交通大学 ， 地质工程， 2013， 博士

【摘要】 近年来,随着铁路工程建设的飞速发展,很多铁路项目在新建过程中无法绕避煤矿及其采空区,采空区对铁路建设的影响越来越大。路基下伏采空区在铁路附加荷载作用下的稳定性评价、铁路不同建筑物下采空区的整治方法及整治范围及深度、整治过程中的采空区应力应变、残余沉降变化及对铁路安全的影响、大型复杂采空区整治的质量及铁路安全评价都是铁路下伏采空区整治过程中需要迫切解决的技术问题。新建东都--平邑线铁路工程在DK1+360～DK3+700经沈村矿区,线路跨越长度达2.16km的地质情况较为复杂的多层大型采空区。该采空区开采时间早,其特征表现为开采规模大、开采无规律、地质条件复杂、开采资料不完善、多次重复开采、采空区层数多等。由于采空区变形,引起地面沉降乃至塌陷及房屋开裂变形等地质现象。该采空区一般具有大型沉陷盆地及小煤窑式古空区塌陷共同存在的特点,是我国铁路建设迄今为止一次性跨越规模最大的采空区,严重影响着东平线铁路的修建和正常运营,初步设计采用的全部处理方案造价高达1.8亿元之巨,约占全线静态投资的15%。论文以该采空区为研究对象,在准确获取采空区各项地质资料及覆岩物理力学参数的基础上,重点开展了以下三项关键技术研究：1)基于三维地质模型的采空区顶板围岩稳定性定量分析评价关键技术。根据本采空区上覆地层变形特征,分别对地表突然坍塌和地表移动盆地残余变形进行分析,计算出采空区各开采煤层采空安全临界埋藏深度及新建铁路线下各区段移动盆地残余变形量,并对铁路下伏采空区顶板进行稳定性评价。为减少采空区处理层数,减小采空区处理深度,根据沿线不同地段分布的采空区的工程地质特征,结合试验段建立4个代表性三维地质模型,分析模拟各层采空区注浆前后顶板围岩应力、应变特点及其稳定性,提出大型多层采空区沿线不同地段注浆加固的深度和层位,即以DK2+200为界,往小里程方向只注浆加固到13“煤采空区,往大里程方向则只注浆加固到15#煤采空区。2)采空区注浆材料配比关键参数的确定。为节约工程造价,对注浆材料大掺量粉煤灰水泥浆液配合比进行室内、外试验研究,分别进行水泥、粉煤灰不同固颗比、不同水灰比下的流动度、凝结时间试验及混合浆液凝结后不同龄期的抗压强度试验,在对试验结果进行分析的基础上,提出大掺量水泥粉煤灰浆液的最佳配合比。3)采空区试验段注浆处理效果检测方法关键技术研究。为确保注浆质量,在对采空区注浆前后场地地球物探特征认真分析的基础上,分别进行注浆前后采空区的直流电测深和浅层地震对比、及注浆前后跨孔电磁波CT和弹性波CT试验对比研究,并进行检测孔注浆量和周围注浆孔注浆量对比分析,在试验成果分析的基础上,提出大型多层采空区注浆质量检测方法应采用点(检查孔)与面(直流电测深)结合、区域(直流电测深)与局部(电磁波CT、弹性波CT)相结合,以及检查孔、注浆孔注浆量对比分析的综合注浆质量检测方法,以确保注浆质量检测的准确可靠。更多还原

【Abstract】 In recent years, with the rapid development of railway engneeering construction, the problem of coal mine and its goaf could not be avoided in many newly-built projects, and the goaf has a more and more important influence on railway construction. Stability evaluation of the goaf beneath the roadbed under the railway additional loads, the remediation method, scope and depth under different loads, the stress and strain in the process of the remediation of the goaf, the residual settlement changes, the quality of the remediation of large and complex goafs and the safety evaluation of railway, all of which are technical issues needed to be urgently solved in the process of the remediation of the goaf beneath the railway.The newly-built railway named Dongdu-Pingyi line goes through the mine of Shen village in the section of DK1+360-DK3+700, acrossing a large complex multi-layer goaf. The mining goaf is about2.16km with a long history, presenting a characteristics of large-scale, multi-layered, mining without rules, complex conditions of hydrogeology and engineering geology, incomplete mining data and repeated exploitation. The goaf deformation causes the ground and the houses to deform, subside, even to sink. It has a characteristic of both large subsidence basin and small coal mines with ancient empty area collapse, which is the largest goaf once acrossed in the railway construction of our country. The existence of the goaf will affect the construction and the normal operation of the Dong-ping railway. The total cost of remediation measures in the preliminary design is up to180million RMB, accounting about15%of the static investment.Taking the such goaf as the research object, based on the geological data and physical and mechanical parameters of the overburden rock, this thesis focuses on the following three key technology:1) The roof rock stability of quantitative analysis and evaluation based on the three-dimensional geological model. According to the deformation characteristics of overlying strata of the goaf, the collapse on the surface and residual deformation of surface mobile basin are respectively analyzed, the critical burial depth for security of each mined coal and residual deformation of moving basin of each section under the newly-built railway line are also calculated and the roof stability beneath the railway is then evaluated. In order to reduce the processing layers and the depth, the four representative three-dimensional geological models are established in the test section, according to the different sections with different distribution of engineering geology characteristics along the railway. And then the stress and strain of the surrounding rock and stability on the roof of each mining layers before and after grouting are analyzed and simulated. So the grouting reinforcement depth and layers of the multilayer goaf along different sections are proposed, that is, taking DK2+200as an example, the grouting for reinforce in that point is only up to the13th layer to the small mileage, while to only up to the15th layer to the big mileage.2) The determination of the key parameters of the ratio of grouting material. To save the engneering cost, indoor and outdoor tests of grouting material mixed with fly ash cement grout ratio are performed, such as test of different water-cement respectively under different ratio of cement and fly ash and different ratio of solid particles, test of different ages and test of compressive strength after the mixed slurry condensation. On the basis of the analysis of the test results, the optimum mixture ratio of the ash cement-fly ash is proposed.3) The comprehensive detection method of grouting treatment in the test section. To ensure the grouting quality, the contrast of DC sounding and shallow seismic, cross-hole electromagnetic wave CT and elastic wave CT test and the grouting amount of checking holes and grouting holes before and after grouting are studied, based on the analysis on the earth geophysical characteristics before and after grouting in the goaf. On the basis of the test results, the comprehensive detection method of grouting treatment to large-scale multi-storey goaf is put forward, that is, it should combine point (check hole) with surface (electrical sounding), combine area (DC sounding) with local (electromagnetic CT、elastic wave CT), and study the contrast of grouting amount of checking holes and grouting holes, to ensure the detection accuracy and reliability of the grouting quality.更多还原