粗粒料及粒间微生物胶结的破碎-强度-能量耗散研究进展

Recent progress on crushing-strength-energy dissipation of coarse granular soil and biocementation at contacts

粗粒料广泛应用于水利大坝、公路铁路路基及机场高填方边坡等对强度及变形要求较高的基础设施中.粗粒料颗粒粒径及颗粒强度离散性较其他岩土颗粒材料大,且在外荷载作用下易发生破碎;微生物胶结作为一种新型的绿色胶结方式,可以改善粗粒料的力学特性,抑制颗粒破碎.文章首先介绍了粗粒料颗粒强度相关理论分析方法:包括Weibull分布理论、尺寸效应、分形维数、雪崩动力学理论等;随后总结了研究粗粒料颗粒强度及变形特性的室内试验方法与技术:包括单颗粒破碎试验、一维压缩试验、声发射监测系统及微生物胶结技术;最后从粗粒料类别、外部环境因素、颗粒粒径、微生物胶结情况等方面对粗粒料单颗粒破碎试验和一维压缩试验结果进行分析,阐明了相关因素对颗粒强度、Weibull模量、压缩性、破碎量、声发射能量及能量耗散等的影响规律.研究成果有助于加深对粗粒料强度及变形特性的认识,也可推动粗粒料在实际工程中的应用.

Coarse granular soil is widely used in infrastructures,such as hydropower dams,road and railways beds and airport high-fill slopes,which have high requirements of strength and deformation.Coarse granular soil has larger particle size and more scattered particle strength than other granular geomaterials.The particles of coarse granular soil are easy to break when subjected to external loading.Biocementaion,as a new promising green technology,has a potential to improve mechanical properties and alleviate particle breakage of coarse granular soil.This review introduce relevant theoretical analysis methods of particle strength of coarse granular soils first,including Weibull distribution,size effect,fractal dimension,avalanche dynamics,etc.Then,laboratory testing technique to investigate the particle strength and deformation characteristics is also introduced,e.g.,single-particle crushing test,one-dimensional compression test,acoustic emission monitoring system and biocementation technology,etc.Finally,results of single-particle crushing test and one-dimensional compression test of coarse granular soil are summarized and analyzed to examine the effects of material properties,external environmental factors,particle size,and biocementation conditions on particle strength,Weibull modulus,compressibility,crushing amount,acoustic emission energy and energy dissipation,etc.This work will deepen the understanding of the particle strength and deformation characteristics of coarse granular soil and promote the application of coarse granular soil in practical engineering.