酶诱导碳酸钙沉淀加固遗址土动力特性试验研究  

Experimental investigation on the dynamic characteristics of earthen site soil treated by enzyme-induced calcium carbonate precipitation

作　　者：原鹏博[1,2] 朱磊 钟秀梅 董兰凤[1,2] 谌文武 YUAN Peng-bo;ZHU Lei;ZZHONG Xiu-mei;DONG Lan-feng;CHEN Wen-Wu(School of Civil Engineering and Mechanics,Lanzhou University,Lanzhou,Gansu 730000,China;Key Laboratory of Mechanics on Disaster and Environment in Western China of Ministry of Education,Lanzhou University,Lanzhou,Gansu 730000,China;Gansu Earthquake Agency,Lanzhou,Gansu 730000,China)

机构地区：[1]兰州大学土木工程与力学学院,甘肃兰州730000 [2]兰州大学西部灾害与环境力学教育部重点实验室,甘肃兰州730000 [3]甘肃省地震局,甘肃兰州730000

出　　处：《岩土力学》2022年第12期3385-3392,3415,共9页Rock and Soil Mechanics

基　　金：国家重点研发计划项目(No.2019YFC1520900,No.2019YFC1520600);秦始皇帝陵博物院青年开放课题(No.Qkfkt202101);地震科技星火计划项目(No.XH21034)。

摘　　要：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/cm^(3)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 in Northwest China, and the earthen sites in this region have been adversely affected by seismic activity for a long time. In order to study the dynamic characteristics of the earthen site soil treated by enzyme-induced calcium carbonate precipitation(EICP), earthen site soil samples with initial dry densities of 1.55, 1.65, and 1.75 g/cm^(3) were subjected to EICP treatment, and a control group without EICP treatment was set up. Dynamic triaxial tests under different confining pressures and vibration frequencies were carried out. The results show that under the same dynamic stress, the dynamic strain of the experimental group is smaller, the energy dissipation is less, and the damping ratio is smaller compared with the control group. After EICP treatment, the dynamic 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 the influence of dry density, confining pressure, and vibration frequency on the model parameter a(dynamic elastic modulus) gradually decreases.Microstructure analysis show that after EICP treatment, calcium carbonate precipitates and adheres to the surface of soil particles,filling the pores, and cementing with the soil particles to form a dense structure, as a result, the strength of the soil structure is improved.

关 键 词：微生物矿化 土遗址 动本构关系 动模量 阻尼比 

分 类 号：TU443[建筑科学—岩土工程]