覆岩隔离注浆充填浆体压缩特性实验与应用

Experimental and applied research on compression properties of slurry used for isolated overburden grout injection

为确定覆岩主注浆层位内充填浆体的应力-变形特征,采用电液伺服万能试验机及自行设计的粉煤灰浆体压缩仪,开展了不同压力下粉煤灰浆体的压缩特性实验研究。结果表明:在覆岩应力的作用下,粉煤灰浆体体积不断减小,减小速率逐渐降低,最终趋于稳定;粉煤灰当量压缩系数随着压力增加而减小,二者近似呈对数关系。基于实验结果,建立了不同注浆充填深度条件下干粉煤灰质量与压实灰体体积的换算关系,进而改进了注采比计算公式,导出了注浆充填干灰质量极限值的计算公式,并进行了工程验证,从而为注浆充填参数设计提供了合理依据。

To study the stress-strain characteristics of the slurry in the main injection horizon of overburden,the experiments on the compressive properties of fly ash slurry under different pressures were conducted by using electro-hydraulic servo universal testing machine and pressure vessel for compression test designed by the authors.The results show that under the action of overburden stress,the volume of fly ash slurry is decreased,and the decrease rate of the slurry reduces gradually;the volume of the slurry is stabilized eventually.The equivalent coefficient of compressibility of fly ash decreases with the increase of pressure,and the relationship between them is found to be logarithmic.Based on the experimental results,the relationship between the weight of fly ash and the volume of compacted fly ash slurry is established under different grouting depths,and the formula of filling ratio is improved.The formula for the limit value of fly ash used for grouting is obtained,and the engineering verification is carried out,which provides a reasonable basis for the design of weight of fly ash in grout injection engineering.