南宁膨胀土直剪蠕变特性及长期强度试验研究  

Experimental Study on Direct Shear Creep Characteristics and Long-term Strength for Nanning Expansive Soil

作　　者：许豪[1] 肖宏彬[2] 滕珂[3] 

机构地区：[1]中国石化集团河南石油勘探局勘察设计研究院,河南南阳473132 [2]中南林业科技大学,湖南长沙410004 [3]中南大学土木建筑学院,湖南长沙410075

出　　处：《公路工程》2011年第1期31-35,40,共6页Highway Engineering

基　　金：国家自然科学基金资助项目(50978097);湖南省自然科学基金资助项目(08JJ3092)

摘　　要：针对南宁膨胀土进行了一系列室内直剪蠕变试验,探讨了南宁非饱和重塑膨胀土在直剪条件下的蠕变特性。试验结果表明:由于膨胀土的膨胀力一直在发生作用,膨胀力抵消了部分竖向荷载,使土的结构变松,加速了剪切蠕变的发展,所以在剪切荷载达到长期抗剪强度极限之后,当竖向荷载足够大时土体表现为以恒定的蠕变速率一直加速蠕变下去,当竖向荷载不够大时土体表现为突然被剪坏;在含水率为16%的条件下土样的长期强度约为短期强度的72.9%,长期强度的指标粘聚力c和内摩擦角均比短期强度的小。On the basis of a series of indoor direct shear creep tests for Nanning expansive soils,creep characteristics under the condition of direct shearing for the unsaturated remodeling expansive soils have been researched.The results shown that the structure of soil has loosened owing to the swelling power offset the part of the vertical load.Therefore,it accelerating the development of shear creep.When the shear load reached the long-term anti-shear strength limit,soil has been accelerated creep down with constant creep rate when the vertical load was large enough.But soil has been suddenly cut when the vertical load was not large enough.The long-term strengths of the soil are about 72.9% of the short-term strengths when water content is 16%.The indicators of long-term strength of the cohesion force c and internal friction angle  was also smaller than that of the short-term strength.

关 键 词：膨胀土 直剪蠕变 长期强度 

分 类 号：U416.03[交通运输工程—道路与铁道工程]