昆明呈贡石灰岩及玄武岩上覆红黏土干缩裂隙对比试验研究  

Comparative experimental study on desiccation cracks of red clay overlying carbonate rocks and basalt in Chenggong,Kunming

作　　者：龙郧铠 张家明[1] 陈茂 陈积普[1] LONG Yun-kai;ZHANG Jia-ming;CHEN Mao;CHEN Ji-pu(Faculty of Civil Engineering and Mechanics,Kunming University of Science and Technology,Kunming 650500,China)

机构地区：[1]昆明理工大学建筑工程学院,云南昆明650500

出　　处：《广西大学学报（自然科学版）》2022年第3期627-636,共10页Journal of Guangxi University（Natural Science Edition）

基　　金：国家自然科学基金项目(41807258)。

摘　　要：为了对比昆明2种不同红黏土的干缩裂隙性,通过室内干燥试验,研究昆明呈贡石灰岩及玄武岩上覆红黏土饱和泥浆样的水分蒸发、干缩裂隙的形成和演化、表面干缩裂隙结构形态。结果表明:石灰岩上覆红黏土(S1)及玄武岩上覆红黏土(S2)的蒸发曲线分为4个阶段,干缩裂隙的形成和演化分为5个阶段;S1的最大蒸发速率、常速率阶段的平均蒸发速率比S2的大,S1的常速率阶段、干燥完成时间比S2的短,减速率阶段比S2长,S1的最终含水率比S2的小;S2的开裂速度快,更容易开裂,但S2的表面裂隙率比S1的小;S1的裂隙条数、裂隙总长度、裂隙平均长度、裂隙平均宽度、土块数比S2的大,S1的土块平均面积、土块最大面积和平均干缩厚度比S2的小。结果表明,2种红黏土的干缩开裂过程有相似之处,但石灰岩上覆红黏土干缩裂隙的发育程度比玄武岩上覆红黏土显著,后者的裂隙形态比前者复杂。In order to compare the desiccation cracks of two different red clay soil in Kunming,based on saturated mud samples,through laboratory desiccation tests,a comparative laboratory study was carried out on the moisture evaporation,formation and development of desiccation cracks,structure and morphology of surface cracks for the red clay overlying carbonate rocks and basalt in Chenggong,Kunming.The results show that the moisture evaporation process can be divided into four stages,the formation and development of shrinkage cracks can be divided into five stages for the red clay overlying carbonate rocks(S1)and basalt(S2);the maximum evaporation rate and the average evaporation rate of the constant rate stage are larger for S1 than those for S2;S1 has shorter constant rate stage and drying completion time than those of S2;the deceleration rate stage for S1 is larger than that for S2;the final moisture content of S1 is lower than that of S2;S2 has a faster cracking speed and is easier to crack,but the surface crack ratio of S2 is smaller than that of S1;the number of crack segments,the total length of the cracks,the average length of the cracks,the average width of the cracks,and the number of aggregates for S1 are large than those for S2.However,the average area of the aggregates,the maximum area of the aggregates and the final thickness of the specimen of S1 are smaller than those of S2.From the tests,we can conclude that the shrinkage and cracking processes of the two red clays is similar,the degree of development of desiccation cracks in the red clay overlying carbonate rocks is more significant than that in the red clay overlying basalt,and the crack morphology of the latter is more complex than that of the former.

关 键 词：红黏土 石灰岩 玄武岩 蒸发 干缩裂隙 

分 类 号：P642[天文地球—工程地质学]