泥灰岩相似材料配比试验研究

Experimental Study on Mix Proportion of Similar Materials of Marl

为了研究泥灰岩具有承载力低,遇水易软化、泥化等特点,采用正交设计试验方法,以粒径为0.3~0.6 mm河砂和325目重晶石粉为骨料,粒径为325目红黏土粉和普通硅酸盐水泥为胶结剂,石膏粉为外掺剂进行泥灰岩相似材料研制。选取相似材料的密度ρ、单轴抗压强度σ_c、弹性模量E、黏聚力C、内摩擦角φ及孔隙率ω为主控物理力学参数,软化系数K_P为主控水理特性参数,通过单轴压缩试验及常规物理试验方法对各主控参数进行了测定。基于测定结果分析了各主控参数极差和方差值,得出各影响因素对各主控参数的敏感性,依据各参数敏感性调节相似材料配合比,确定出泥灰岩相似材料最佳配合比。并对该配合比下相似材料破坏的应力-应变曲线及水理特性进行分析。研究结果表明:骨胶比对单轴抗压强度σ_c、密度ρ、黏聚力C、弹性模量E及孔隙率ω最为敏感;内摩擦角φ对黏土∶水泥最为敏感;软化系数K_P对砂∶重晶石最为敏感。当骨胶比为1∶1,黏土∶水泥为2∶1,砂∶重晶石为2∶1,石膏掺量为30%时,可较好地对泥灰岩特性进行模拟,该配合比下的相似材料能模拟出岩石破坏的力学特性及泥灰岩遇水软化、泥化的水理特性。

In order to study the characteristics of marl such as low bearing capacity,easy to soften and sliming in water,using the river sand with particle size of 0.3-0.6 mm and the barite powder particle size of 325 mesh as the aggregates,the red clay powder with particle size of 325 mesh and the ordinary Portland cement as the cementing agent,and the gypsum powder as the admixture,the similar materials of marl are developed by orthogonal design test method.Selecting densityρ,uniaxial compressive strengthσ_c,elastic modulus E,cohesion C,internal friction angleφand porosityωof similar materials as the main controlling physical and mechanical parameters,and softening coefficient K_P as the main controlling hydraulic characteristic parameter,the main control parameters are measured through uniaxial compression test and conventional physical experiment method.Based on the measurement result,the range and the variance of each main control parameter are analyzed,and the sensitivity of each influencing factor to each main control parameter is obtained.According to the sensitivity of each parameter,the mix proportion of similar materials are adjusted to determine the best mix proportion of similar material of marl,and the stress-strain curve and the hydraulic characteristics of similar materials under this mix proportion are analyzed.The research result shows that(1)aggregate-cement ratio is most sensitive to uniaxial compressive strengthσ_c,densityρ,cohesion C,elastic modulus E and porosityω;(2)internal friction angleφis most sensitive to clay-cement ratio;(3)softening coefficient K_P is most sensitive to sand-barite ratio;(4)when the aggregate-cement ratio is 1∶1,the clay-cement ratio is cement 2∶1,the sand-barite ratio is 2∶1,and the content of gypsum is 30%,the characteristics of marl can be better simulated,the mechanical properties of rock failure and the hydraulic characteristics of marl softening and sliming can be simulated by using the similar material under these mix ratios.