某地红黏土收缩性引起低层建筑开裂机理分析

Analysis on Cracking Mechanism of Low Rise Building by Red Clay Shrinkage

为揭示清镇市红枫湖镇大冲村低层建筑墙体开裂机理,该文选择红黏土地基上具有代表性的单层民房为例,在对墙体开裂特性、地基外部条件进行调查评价的基础上,按照固结作用计算房前水泥硬化地面的地基沉降值;采用收缩作用计算房后红黏土出露地表大气影响深度范围的地基沉降值,结果表明二者之间较大的沉降差是引起民房开裂的主要原因。进一步研究表明,1~2层房屋裂缝是由红黏土的收缩变形大于压缩变形引起的地基不均匀沉降造成的;而3~4层建筑物荷重较大,附加应力所引起的地基土压缩效应大于其收缩变形且抑制了膨胀压力的产生,表现为均匀沉降而很少开裂。

In order to reveal the wall cracking mechanism of low-rise buildings in Dachong Village,Hongfenghu Town,Qingzhen City,this paper selects a representative single-storey civil house on the red clay foundation as an example.Based on the investigation and evaluation of the wall cracking characteristics and the external conditions of the foundation,the foundation settlement of the cement hardened ground in front of the house is calculated according to the consolidation effect;The foundation settlement value of the exposed surface atmospheric influence depth range of red clay behind the house is calculated by shrinkage.The results show that the large settlement difference between them is the main reason for the cracking of civil houses.The further research shows that the cracks of 1~2 storey buildings are caused by the uneven settlement of foundation because the shrinkage deformation of red clay is greater than the compression deformation;The load of 3~4 buildings is large,the compression effect of foundation soil caused by additional stress is greater than its shrinkage deformation,and the generation of expansion pressure is restrained,which is characterized by uniform settlement and few cracking.