YUAN Peng-bo, ZHU Lei, ZHONG Xiu-mei, et al. Experimental investigation on the dynamic characteristics of earthen site soil treated by enzyme-induced calcium carbonate precipitation[J]. 2022, 43(12): 3385-3392.
YUAN Peng-bo, ZHU Lei, ZHONG Xiu-mei, et al. Experimental investigation on the dynamic characteristics of earthen site soil treated by enzyme-induced calcium carbonate precipitation[J]. 2022, 43(12): 3385-3392.DOI: 10.16285/j.rsm.2022.0172.
中国西北地区地震频发,土遗址长期受到地震活动的不利影响。为了研究酶诱导碳酸钙沉淀技术(EICP)加固遗址土的动力特性,对1.55、1.65、1.75 g/cm3这3种初始干密度的遗址土进行EICP处理,并设置未经EICP处理的对照组。开展了不同围压、振动频率下的动三轴试验。结果表明:在相同动应力作用下,相比对照组,试验组的动应变更小,耗散的能量更少,阻尼比更小;在EICP加固后,随着干密度、围压、振动频率增大,可以降低动应变的产生,但这种效果依次减弱。动本构关系符合Hardin模型,干密度、围压、振动频率对模型参数a(动弹性模量)的影响程度逐渐减小;微观分析发现,EICP加固后,碳酸钙沉淀在土颗粒表面附着,填充孔隙,并与土颗粒相互胶结成致密结构,土体结构强度增强。Earthquakes are frequent inNorthwest China
and the earthen sites in this region have been adverselyaffected by seismic activity for a long time. In order to study the dynamiccharacteristics of the earthen site soiltreated by enzyme-induced calcium carbonate precipitation (EICP)
earthen sitesoil samples with initial dry densities of 1.55
1.65
and 1.75 g/cm3 were subjected to EICP treatment
and acontrol group without EICP treatment was set up. Dynamic triaxial tests underdifferent confining pressures and vibration frequencies were carried out. Theresults show that under the same dynamic stress
the dynamic strain of theexperimental group is smaller
the energy dissipation is less
and the dampingratio is smaller compared with the control group. After EICP treatment
thedynamic strain could be reduced with the increasing of the dry density
confining pressure
and vibration frequency but this effect diminishes in turn.The dynamic constitutive relation is in line with the Hardin model
and theinfluence of dry density
confining pressure
and vibration frequency on themodel parameter a (dynamic elastic modulus) gradually decreases. Microstructureanalysis show that after EICP treatment
calcium carbonate precipitates andadheres to the surface of soil particles
filling the pores
and cementing withthe soil particles to form a dense structure