基于SHPB的砒砂岩地聚物水泥复合土动态力学特性  

Dynamic mechanical properties of Pisha sandstone geopolymer cement composite soil using SHPB

作　　者：赵晓泽 李晓丽[1] 申向东[1] 杨健 Zhao Xiaoze;Li Xiaoli;Shen Xiangdong;Yang Jian(College of Water Conservancy and Civil Engineering,Inner Mongolia Agricultural University,Hohhot 010018,China)

机构地区：[1]内蒙古农业大学水利与土木建筑工程学院,呼和浩特010018

出　　处：《农业工程学报》2021年第17期310-316,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(51869022);内蒙古自然科学基金资助项目(2020MS05051)。

摘　　要：为探究砒砂岩地聚物水泥复合土在冲击载荷作用下的力学性能,实现大量松散砒砂岩在农业工程的有效利用,该研究通过分离式霍普金森压杆(Split Hopkinson Pressure Bars,SHPB)冲击试验,探究了不同应变率下砒砂岩地聚物水泥复合土的力学特性。通过破碎颗粒筛分统计,得到了砒砂岩地聚物水泥复合土在冲击荷载作用下的破碎特征,从能量的角度建立了不同冲击荷载作用与砒砂岩碎块平均块径及分形维数的相关关系。结果表明:砒砂岩地聚物水泥复合土动力增大系数与应变率密切相关,当应变率小于64.67 s^(-1)时,动力增大系数与应变率对数呈线性关系,当应变率大于等于64.67 s^(-1)时,动力增大系数与应变率对数呈非线性关系。随着能量吸收通量密度的增大,试块破碎平均块径呈幂函数减小,分形维数先减小后增大;在能量吸收通量密度为29.08 J/(s·m^(2))时出现分界点,此时分形维数最小,破碎块体粒径最不均匀;当小于该分界点时,分形维数随能量吸收通量密度的增大不断减小,当大于等于该分界点时,分形维数呈幂函数上升。该研究可为砒砂岩地聚物水泥复合土在农业水利中用作田间排水或输水工程材料及农村道路铺设路基材料等提供参考。Pisha sandstone is widely distributed over the Ordos Plateau in Inner Mongolia,China.This loose rock layer is prone to soil erosion,due to the small overburden thickness,low pressure,low degree of rock formation,and inter-sand cementation.Fortunately,Pisha sandstone can serve as the main body to prepare the Pisha sandstone geopolymer cement composite soil using alkali excitation.The composite soil can also be applied to the channel lining for environmental protection in the cold areas of northern China,where the impact load usually happens,such as ice cream,and sandy water flow.In this study,the dynamic mechanical properties of Pisha sandstone geopolymer cement composite soil were investigated under various impact loads.A test was also carried out usingΦ80 mm Split Hopkinson Pressure Bars(SHPB)with the air pressures from 0.04 to 0.3 MPa for various strain rates,thereby exploring the kinetic properties of Pisha sandstone ground aggregate cement composite.The results showed that the strain rate of Pisha sandstone geopolymer cement composite soil increased significantly,with the increase of impact air pressure,whereas,the growth rate decreased after the strain rate exceeding 161.69 s-1.Specifically,the dynamic modulus of elasticity of composite soil was relatively stable and grew less with the increase of strain rate when the strain rate was less than 64.67 s-1,whereas,the dynamic modulus of elasticity grew rapidly with the increase of strain rate,when the strain rate was greater than 64.67 s^(-1).A significant parameter,the dynamic increase coefficient(the ratio of dynamic strength to static strength)was also selected to evaluate the dynamic performance of cement soil.As such,the dynamic increase coefficient presented a linear relationship with the logarithm of strain rate,when the strain rate was less than 64.67 s^(-1),whereas,a nonlinear relationship with the logarithm of strain rate was found,when the strain rate was greater than 64.67 s-1.Furthermore,the continuous fracture was observed to break into several s

关 键 词：应变率 能量吸收 动态响应 分离式霍普金森压杆 破碎特征 砒砂岩 

分 类 号：TU525[建筑科学—建筑技术科学]