奥灰顶部含水层注浆改造浆液扩散主要影响因素试验研究

Experimental study on the influence of grouting diffusion in fissure aquifer at the top Ordovician limestone

为探究浆液黏度、溶蚀裂隙及岩溶孔洞对注浆改造过程中浆液在奥陶系顶部灰岩裂隙含水层中扩散、充填影响规律,自行研制一套可考虑裂隙分布、动承压水和注浆工艺因素的裂隙岩体动水注浆改造模型实验台。利用该装置模拟了3种黏度浆液在4类含岩溶裂隙、孔洞分布条件下的承压含水层中的扩散过程,总结了浆液扩散及充填规律;结合数值计算得到了11组注浆实验充填过程中应力分布及变化规律;最后通过超声波探测,分析了不同条件下浆液改造后岩体弹模变化规律。结果表明:①均布裂隙中浆液扩散形态接近“∩”形,考虑不同条件作用后的浆液扩散形态呈现出非标准圆弧形;含有岩溶优势裂隙的浆液扩散形态呈现“Λ”形,裂隙开度越大,“Λ”形顶角越小;含岩溶孔洞的裂隙区浆液扩散形态出现“M”形,存在“︹”形的过渡形态。②注浆改造后的裂隙岩体具有分区特性,可将其分为完全充填(FF)、部分充填(PF)、裂隙二次发育(DeF)和原岩裂隙(OF)4个区域;极差结果显示裂隙开度对S_(FF)影响最大,浆液黏度对S PF影响最大;③溶蚀裂隙和岩溶孔洞经注浆改造后弹性模量明显增强,裂隙中的浆液压力分布呈现非线性递减,且裂隙岩体基质受到的应力大小和作用时间影响与改造后岩体动弹模成正比。

In order to explore the influence of slurry viscosity,dissolution fracture surfaces and karst cavities on slurry diffusion and filling in fractures during grouting reinforcement and reconstruction,a set of dynamic water grouting model testbed for fractured rock mass was developed,and the fracture distribution,dynamic confined water and grouting technology factors can be considered during experiment.First,the device was used to simulate the diffusion process of three kinds of viscosity slurries in four types of confined aquifers with karst fissures and holes distribution.Then the laws of slurry diffusion and filling were summarized.Combined with numerical simulation,the stress distribution and variation law of fractured rock mass were obtained from 11 sets of grouting tests during the filling process of grouting.At last,the changing rule of rock elastic modulus after slurry transformation under different conditions was analyzed by ultrasonic detection.The results demonstrated that①the slurry diffusion pattern after considering different conditions shows a non-standard arc shape.Specifically,the slurry diffusion pattern in uniformly distributed fissures is close to the“∩”shape.The dominant fissure containing karst is“Λ”shape and the apex angle is smaller with the increase of the fracture opening.In the fissure zone containing karst cavities is“M”shape with transition form of“︹”shaped;②The fractured rock after grouting transformation has zoning characteristics,which can be divided into four areas:full filling(FF),partial filling(PF),fracture development filling(DeF)and original rock fracture(OF);③After grouting,the elastic modulus of karst fractures and karst pores was significantly enhanced,and the distribution of slurry pressure in fractures presented a nonlinear decline.Moreover,the effect of stress and action time on the matrix of fractured rock mass were directly proportional to the dynamic modulus of rock mass after grouting.