| 摘要: |
| 【目的】研究膨胀土在增湿过程中的膨胀变形规律，提出膨胀土在侧限条件下的增湿变形计算模式。【方法】以采自安康的膨胀土为试样，在压缩仪上对不同初始干密度的试样分别进行无荷载分级浸水试验、无荷载分级浸水变形稳定后的压缩试验、有荷载分级浸水及一次性浸水变形试验，测定膨胀土在浸水过程中的变形情况，分析总结其变形规律，提出其增湿变形计算模式，并对提出的计算模式进行验证。【结果】无荷载作用下的分级浸水试验中，各试样的膨胀率均随着含水率的增加而增大；浸水变形稳定后对其进行压缩试验，各试样膨胀率随着垂直压力的增大而减小。试样在有荷载分级浸水试验中，在较大压力下，膨胀率随着含水率的增大先稍有增加，后又减小而表现为压缩变形；在压力较小时，试样的膨胀率基本上是随着含水率的增加而增大；在含水率增加到饱和状态时，膨胀变形趋于稳定。有荷载一次性浸水变形试验中，试样所受压力越小，膨胀率越大；初始干密度越大，膨胀率也越大。提出了如下增湿变形计算模式：无荷载作用下不同初始干密度膨胀土在分级浸水过程中，膨胀率随含水率增加的变化符合双曲线规律；浸水变形稳定后进行压缩试验，试样膨胀率与压力的关系呈双曲线规律。有荷载作用下膨胀土分级浸水试验中，试样含水率的累积增加量与膨胀率的变化规律基本符合二次曲线关系；试样在压缩稳定后一次性浸水变形试验中，最大膨胀率与初始干密度呈线性变化规律。【结论】提出了侧限条件下膨胀土增湿变形的计算模式，将计算模式用于宁夏某渠道地基变形分析，结果基本符合实际情况。用该模式对试验结果进行回判分析，计算数值与试验数据吻合较好。 |
| 关键词: 岩土工程 膨胀土 增湿变形 计算模式 |
| DOI： |
| 分类号: |
| 基金项目:水利部“948”计划技术创新与转化项目（200408）；西北农林科技大学科研专项面上项目（04ZM074） |
|
| Study on the calculation methods of the moistening deformation for the expansive soil under lateral restraint condition |
|
|
| Abstract: |
| 【Objective】The study was done to learn the swelling deformation regularity for the expansive soil during the course of the moistening and to propose the moistening deformation calculation methods.【Method】Using compressometer for the expansive soil in AnKang does stage immersion test without load,compression test after stage inundation swelling steady without load,stage inundation saturation swelling test under loading,one moistening deformation test under loading,the moistening deformation regularity was analyzed for the expansive soil in inundation course.【Result】The swelling deformation rate increased along with the broadening of water content for the expansive soil in the test of stage immersion test without load;The swelling deformation rate decreased along with the increase of vertical pressure for the expansive soil in compression test after stage inundation swelling steady;In the stage inundation saturation swelling test,the swelling deformation rate increased along with the broadening of water content in beginning,afterwards it decreased when the pressure was greater,the swelling deformation rate increased along with the broadening of water content when the pressure was smaller,and the swelling deformation rate was steady when inundation attained saturation conditions;In the one moistening deformation test under loading,the pressure was smaller,the swelling deformation rate is greater,the original dry density smaller,the swelling deformation rate greater too.The moistening deformation calculation methods were analyzed and proposed,the swelling deformation rate and the accumulation water content were accord with the hyperbolic curve for the expansive soil in stage immersion test without load;the inundated samples added different pressures after deformation steady,the deformation rate and the pressure were accord with the hyperbolic curve.The accumulation water content and the swelling deformation rate possibly were accord with the conic section for the same initial condition samples in the processes of stages inundated under different pressures.In the inundated swelling after compressive deformation steady,the largest swelling rates and original dry densities were accord with linear variety regular pattern for the samples in the condition of different original dry density and same original water content.【Conclusion】The moistening deformation calculation methods were proposed.The calculation results indicated that the calculation numeric value was accord with test data,and using the calculation methods to calculate ground deformation for the some irrigation ditch of NingXia,the calculation numeric value was accord with the actual value. |
| Key words: geotechnical engineering the expansive soil moistening deformation calculation methods |
