干湿循环效应对风化泥岩性质影响的试验研究  

Test Study on Properties of Weathered Mudstone under Wetting-drying Cycle

作　　者：王亚坤[1,2] 张文慧[1,2] 陈涛[1,2] 蓝日彦 叶琼瑶 雷文[1,2] 

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098 [2]河海大学岩土工程科学研究所,江苏南京210098 [3]广西交通规划勘察设计研究院,广西南宁530011

出　　处：《公路工程》2013年第2期94-98,共5页Highway Engineering

摘　　要：风化泥岩除了一般泥岩的崩解性质以外还受季节性气候的影响,其强度具有明显的变动特性。如果能够得到风化泥岩的强度随干湿循环的变化规律,可为实际工程需要提供可靠的数据,具有重要的理论意义和工程意义。因此对广西南宁柳南路段高速公路的风化泥岩进行干湿循环的试验研究,包括干湿循环条件下的直剪试验和CBR强度试验,实验结果表明:由于干湿循环破坏了土的原有结构,使泥岩结构崩解,凝聚力减小,从而导致风化泥岩的抗剪强度和CBR强度逐渐减小,并且减小趋势随循环次数的增多而减小,内摩擦角也会稍微减小,抗剪强度的衰减主要体现在前两次干湿循环过程中,其粘聚力和内摩擦角在前两次循环中递减的厉害,但是在后几次循环中变化不大;干湿循环过程中风化泥岩的膨胀率随循环次数逐渐减小,这点是因为风化泥岩结构在崩解的过程中趋于稳定,而且如果有上覆压力的作用时,膨胀率会更小。Besides the general character of degradation of the mudstone, the prominent character- istic of mudstone is its strength that has the obvious varying property with the changing of seasonal cli- mate. If we can get the the change law of mudstone with the strength of wetting-drying cycle ,we can sup- ply the reliable data for practical engineering which has important theoretical and constructing meaning. Wetting-drying cycle in mudstone is studied by experiments, and the mudstone is got from the liu nan highway in the city of nan ning in guang xi province. The experiments include direct shear test and the CBR strength test in the condition of wetting-drying cycle. Through analyzing the experimental data, some conclusions can be found out：The original structure of the mudstone is destroyed by the wetting-dr- ying cycle which make the structure degradation and the cohesion is reduced, and so the shear strength and CBR strength are reduced gradually. The trend of reduction is decreased with the increase of the time of wetting-drying cycle. The internal friction angle will decrease a little,and the attenuation of the shear strength is mainly expressed in the first two wetting-drying cycle. The cohesion and the internal friction angle reduced heavily in the first two cycles and change a little in another cycles. In the wetting-drying cycle the expansion rate of the mudstone is reduced gradually. The reason is that the structure of the mudstone become stable in the process of degradation and if there is some load on the mudstone ,the ex- pansion rate will be more little.

关 键 词：风化泥岩 干湿循环 抗剪强度 CBR 膨胀率 

分 类 号：U416.16[交通运输工程—道路与铁道工程]