黄土窑洞“人文层”厚度及宏微观性质  

Thickness and Macroscopic & Microscopic Characteristics of the “Circle Thickness Affected by Human Activities” of Loess Cave Dwellings

作　　者：王念秦[1] 张帅[1] 杨盼盼[1] WANG Nian-qin;ZHANG Shuai;YANG Pan-pan(College of Geology&Environment,Xi'an University of Science&Technology,Xi'an 710054,China)

机构地区：[1]西安科技大学地质与环境学院,西安710054

出　　处：《科学技术与工程》2018年第10期267-272,共6页Science Technology and Engineering

基　　金：国家自然科学基金面上项目(41572287);陕西省科技统筹创新工程计划(2016KTCL03-19);陕西省煤田地质局科技计划(JB2014-4)资助

摘　　要：人类正在使用的黄土窑洞通常较废弃窑洞更加稳定,为揭示这一现象的机理,提出黄土窑洞"人文层"的概念,并借助室内土工试验和SEM系统测试在用窑洞洞壁一定厚度范围内土体宏观物理力学性质及微观特征,以期揭示黄土窑洞"人文层"厚度及基本特征。试验结果表明:探洞揭露范围内洞壁黄土含水率介于3.32%~7.24%;天然密度介于1.33~1.55 g/cm^3;干密度介于1.24~1.48 g/cm^3;100 kPa压力下剪切强度介于78.00~157.61 kPa。分析可得四点结论:(1)黄土窑洞"人文层"客观存在,在其厚度内,土体含水率、天然密度和干密度变幅很小;(2)"人文层"厚度可以通过窑洞洞壁土体表观特征、含水率、天然密度、干密度和剪切强度变化曲线拐点综合确定。试验黄土窑洞"人文层"厚度51~61 cm;(3)"人文层"黄土具有干燥、致密和高强度的宏观特征,有利于窑洞整体稳定;(4)微观上"人文层"黄土土粒多以团块形式存在,接触方式以镶嵌接触为主,空隙面积极小、数量极少且多为点线状。Generally,the cave dwellings which are being used are more stable than those abandoned.To reveal its mechanism,the concept of“circle thickness affected by human activities”(called“humanistic circle”for short)was proposed and the macroscopic physical and mechanical characteristics and the microscopic features of loess of cavity wall in an active cave dwelling were tested systematically using the laboratory soil experiments to reveal the thickness and general characteristics of“humanistic circle”.The experiment results showed that in the range has been revealed by testing tunnel,the moisture content of loess of cavity wall is 3.32%~7.24%;the natural density is 1.33~1.55 g/cm 3;the dry density is 1.24~1.48 g/cm 3;the shear strength under 100 kPa vertical pressure is 78.00~157.61 kPa.By analyzing,four conclusions were found out.①The“humanistic circle”of the loess cave dwelling exists objectively.In the range of“humanistic circle”,loess moisture content,natural density and dry density change slightly.②Thickness of“humanistic circle”can be determined comprehensively by the loess appearance features and inflection points of variation curves of moisture content,natural density,dry density and shear strength,and thickness of“humanistic circle”of the testing cave dwelling is 51~61 cm.③The general physical and mechanical characteristics of loess of“humanistic circle”are dry,compacting,and high-strength which are beneficial to the stability of cave dwellings.④Most loess particles of“humanistic circle”aggregate into crumbs,and the main contact type is inlaid contact.The area and amount of voids which are on the form of line and spot are very small.

关 键 词：“人文层” 黄土窑洞 窑洞壁黄土特征 塌窑 微观结构 

分 类 号：TU929[建筑科学—建筑设计及理论]