炎热多雨和突降暴雨气候影响下玄武岩残积土的崩解试验研究

Experimental investigation on relative contribution of hot and humid weather and heavy rainfall in disintegration of basalt residual soil

气候环境是影响玄武岩残积土崩解特性的重要因素.为研究高温湿热与突降暴雨气候影响下玄武岩残积土的崩解特征,我们开展了反复干湿循环过程后的大气崩解试验与浸水崩解试验,通过崩解率、崩解速率及崩解物的颗粒组成评价了崩解特性的气候影响控制因素.研究结果表明,高温湿热气候引起的反复干湿交替会破坏颗粒团聚性,增强土的分散性,随着干湿循环次数的增加,崩解率与崩解速率增大,崩解物由粗颗粒为主逐渐转为细颗粒为主,气温越高、气候变化越剧烈,这种影响越显著.突降暴雨气候会引发玄武岩残积土剧烈的崩解现象,随着干湿循环次数的增加,崩解物由碎屑状向泥状过渡,崩解速率增大,崩解程度逐渐增强.研究还发现,除了气候环境影响,施工扰动也会促进崩解的发生,施工中应加强监测气候环境变化对崩解性的影响,必要时需对玄武岩残积土工程进行保湿、防水措施.

Basalt residual soil presents strong disintegration phenomenon by climatic influence. In order to understand the relative contribution on hot and humid weather and frequent heavy rainfall in disintegration of basalt residual soil, basalt residual soils were first subjected to wetting-drying cycles, and then were used for disintegration test in atmosphere and in soaking to simulate the effect of the climate change, based on a series of indexes such as disintegration rate, disintegration velocity and disintegrative deposits characteristics. The results showed that hot and humid weather could damage the aggregation between particles and facilitated the dispersibility of soil, and the majority of disintegrative deposits translate from coarse to fine, which in turn may lead to severe disintegration. While sudden heavy rain contributed to more severe disintegration, and with the increment of wetting-drying cycles, disintegrative deposits turn from lump or fragment to powder, and translate to mud, disintegration velocity increases and disintegration tends to a more severe extent. Based on the experimental findings, a disintegration classification for basalt residual soil is suggested in order to determine and evaluate disintegration characteristics according to the laboratory test results.