压实方式影响路基湿度场演变规律相似模拟试验研究

Simulation test on evolutions of subgrade humidity field affected by compaction methods

探究路基湿度场演变规律是解决路基工程水损害的基础问题之一,为研究路基湿度场受压实方式影响所产生的变化与分布问题,在相似准则推导的基础上构建了4种具备不同压实方式的室内路基相似物理试验模型。通过分析二维入渗方式的降雨试验结果,总结了不同压实方式影响下路床湿度场扰动区扩距、前扰动区湿度分布、湿度梯度和路堤湿度值变化的主要规律,并阐述其作用机制以及提出了相关工程建议。研究结果表明:路床湿度扰动区扩距随着路床压实度的增加呈线性递减;整个湿度扰动区可划分为前、后两个区域,前扰动区湿度分布基本呈线性速降状态,湿度梯度值随着路床压实度的增加呈线性提高;路床压实度对其下的路堤湿度影响效果显著,综合效应表现为路堤湿度随路床压实度增加呈线性递减;工程中严格控制上部路基压实效果对防止下部路基水毁病害有显著作用。

As one of the basic issues, the evolutions of humidity field must be studied to avoid roadbed water damage. To study changes and distributions of the subgrade humidity field affected by compaction methods, 4 kinds of scale-down laboratory subgrade physical models with different compaction methods were tested. Through analyzing tow-dimensional infiltration rainfall test results, the influences of different compaction methods on the extended distances in roadbed humidity disturbed zone, humidity distributions in front disturbed zone, humidity gradients and humidity values of embankment were summarized. Their mechanisms were explained and relevant engineering suggestions were proposed. The results show that extended distances in roadbed humidity disturbed zone decrease linearly with the increase of compaction degree. The whole humidity disturbed zone can be divided into front and back zones. The front zone humidity shows a quick linear decrease distribution and humidity gradient increases linearly with the increase of roadbed compaction degree. Embankment humidity is affected significantly by the compaction degree of its upper roadbed. The combined effect reveals that embankment humidity decreases linearly with the increase of roadbed compaction degree. It should place a strict control on the upper subgrade impaction to avoid deeper subgrade damages due to water in engineering construction.