幂律型流体劈裂注浆机理研究

劈裂注浆技术已广泛应用于各种地下工程之中,但其理论研究远落后于工程实践。为了明确幂律型流体劈裂注浆机理,基于平板裂缝模型及幂律型流变方程,推导出幂律型流体劈裂注浆最大扩散半径计算公式,并分析其适用范围及参数确定方法,最后通过现场注浆试验对其进行验证。结果表明:① 劈裂注浆最大扩散半径与起裂注浆压力、浆液锋前压力、裂缝劈裂宽度、黏度系数、浆液平均流动速率及流变指数等有关;②通过分析浆液最大扩散半径与注浆压力差之间的关系,发现注浆压力差越大,浆液最大扩散半径越大;同时,根据裂缝宽度与浆液压力差的关系,可知裂缝宽度越大,所需要的注浆压力差越小;③根据工程试验结果,得到幂律型流体劈裂注浆最大扩散半径理论计算值与实际测量值之间的误差,验证了幂律型流体劈裂注浆最大扩散半径计算公式的正确性与可行性。研究成果可为同类型注浆工程提供一定的理论支撑与技术支持。

Mechanism of Fracture Grouting of Power-law Fluid

Though fracture grouting technique has been widely used in underground engineering, the theoretical study lags far behind engineering practice. Based on the assumption of power-law fluid and narrow plate model of grouting diffusion, a formula for calculating the maximum diffusion radius of a power-law fluid is deduced. The scope of application and the method to determine parameters are analyzed, and the formula is validated by means of filed grouting tests. The findings are as follows: 1) the maximum diffusion radius of fracture grouting is related to grouting pressure, front surface pressure, crack width, viscocity coefficient, average flow rate of grout and flow behavior index; 2) the maximum diffusion radius increases with grouting pressure difference, and grouting pressure difference reduces with the increase of crack width; 3) according to field test results, the error between theoretical calculation value and actual measured value of the maximum diffusion radius of the power-law fluid is obtained, which proves that the formula is correct and applicable. The results provide theoretical and technical support for similar grouting projects.