轻量土最优含水率模型与检验

Optimum water content models and tests of light weight soil

为确定不同配比轻量土的最优含水率,提出ρd-w模型,qu-w模型,RS-w模型3种最优含水率模型,假设3种模型可以统一表示为开口向下的抛物线函数,从理论上推导出了最优含水率解析式。为检验3种最优含水率模型及确定模型系数,通过试验对轻量土物理力学特性进行了研究。结果表明:轻量土的干密度、无侧限抗压强度、比强随着含水率的增大,先增大后减小,存在最优含水率,曲线形态类似于抛物线。用3种最优含水率模型对实测数据进行回归分析,模型计算得到的最优含水率与图解法直接得到的含水率值是极其接近的。结合前人成果,qu-w模型,RS-w模型对应的最优含水率几乎相同,而与ρd-w模型对应的含水率略有差别,3种模型对应的最优含水率基本上是相同的。轻量土的最优含水率为混合物物理需水与化学需水的总和,是复杂物理化学反应需水量的外在表现,是3种模型具有统一性的理论基础。以RS-w模型为例,计算出了轻量土各组分的质量需水率,与原材料性质关系较为密切。

To determine the optimum water content of light weight soil with different mixture proportions,three kinds of models for the optimum water content are put forward：-w model,qu-w model and RS-w model.It is supposed that three models can be expressed as a uniform downward opening parabola function.Analytic expressions for the optimum water content are theoretically derived.To test the above three models and to determine model coefficients,physical mechanical properties of light weight soil are studied by laboratory tests.The results show that the dry density,unconfined compressive strength and specific strength first increase and then decrease with the increase of water content,each of them has an optimum water content,and their curve shapes are similar to parabola.The measured data are analyzed based on the three models,the optimum water content calculated by models are very close to that obtained directly by the graphic method.By use of the precursors＇ research achievements,the corresponding optimum water contents of qu-w model and RS-w model are almost the same,but they are slightly different from the corresponding optimum water content of-w model.The optimum water contents of the three models are essentially the same.The optimum water content of light weight soil is the sum of physical and chemical water demand,it is an external appearance of water demand of complex physical and chemical reactions,and it is a theoretical basis for the three models to be unified.Taking RS-w model for an example,the water demand rate of mass of different components are calculated,and the results are closely related to properties of materials.