水电工程大坝基岩三维随机裂隙岩体灌浆数值模拟

THREE-DIMENSIONAL NUMERICAL SIMULATION OF GROUTING IN STOCHASTIC FRACTURE NETWORK OF DAM BEDROCK IN HYDROPOWER ENGINEERING

针对目前裂隙岩体灌浆数值模拟主要以单一裂隙或者二维裂隙网络为研究对象,且多未考虑隙宽随机性分布的现状,该文首先利用Monte-Carlo方法构建隙宽服从随机分布且耦合灌浆孔的三维随机裂隙网络灌浆模型;然后采用三维离散元软件(3DEC)模拟多级水灰比浆液在裂隙网络中的扩散过程,并分析压力场、单宽流量场的分布特征。运用该方法模拟某水电站灌浆孔基岩帷幕灌浆过程,结果表明:压力由灌浆孔壁向裂隙内呈非线性衰减,在灌浆孔附近压力衰减速率最快;浆液流量因水灰比的逐级变浓而随着灌浆时间的增加呈阶梯状下降;将模拟灌浆量和灌浆时间与实际值对比,相对误差分别为-17.11%和3.11%,模拟结果与实际值基本吻合,验证了该方法的可用性。

The present research objects of the grouting numerical simulation of fractured rock mass focus on a single facture or two-dimensional fracture network, while the randomness of aperture distribution has been seldom considered. Aiming at above problem, a three-dimensional stochastic fracture network model for grouting numerical simulation coupled with the randomly distributed aperture and grout hole is firstly established, based on the Monte-Carlo method. Then, the three-dimensional distinct element code （3DEC） is employed to simulate the grout diffusion process with a multistage water-cement ratio in the fracture network, and the distribution characteristics of pressure field and flow field of unit width are analyzed. Finally, the bedrock curtain grouting process of a grouting hole in a hydropower station is taken as a ease. Research results show that： the pressure attenuation trend of cement grout is nonlinear from the grouting hole, in the vicinity of which the pressure decreases the fastest; because of the water cement ratio becoming thicker gradually, slurry flow rate decreases as a ladder pattern with the increase of grout time. Furthermore, comparing the simulation value with the actual measuring value of the grouting quantity and time, the relative errors are -17.11% and 3.11%, respectively, which verifies the availability of the method.