侧限条件下膨胀土膨胀变形试验研究

利用弹性力学的有关理论分析了侧限膨胀试验中土样的受力和变形特点,推导出了在无荷膨胀试验条件下,膨胀土膨胀系数的理论计算公式;针对南宁-友谊关公路宁明段灰黑色膨胀土填料进行了侧限有荷膨胀试验,利用有荷试验结果推导出了膨胀土在侧向约束、上部加压条件下膨胀应变与含水率、上部荷载之间的计算关系式。结果表明:上覆压力对膨胀变形起拟制作用,在其他条件不变的情况下,上覆压力越大,则膨胀变形量越小;膨胀土是对含水量变化特别敏感的土体,含水量增加是土体膨胀的直接原因,膨胀量与吸水量紧密相关,且与(w-w0)成正比关系;利用无荷试验确定了湿度膨胀系数的测定方法,并用试验结果对南友路膨胀土路堤的修筑提出了一些建议。

Experimental Research on Lateral Restricted Swelling Strain of Expansive Soil

Mechnical and deformation characters of expansive soil specimens subjected to lateral restricted load experiment are analyzed by related theory of elastic mechnics.A formula for calculating swelling coefficient of expansive soils is conducted under condition of nonload experiment.in succession,a formula for calculating lateral loaded swelling ratio of expansive soils varying with moisture content and upper load is established by adopting lateral restricted loaded swelling experiment.It shows that,upper loads can restrict swelling deformation,while the other conditions unchanged,the greater the upper loads,the smaller the swelling ratio;expansive soil is sensitive to change of water content which is direct cause of soil swelling strain generation;loaded swelling ratio is closely related to absorption moisture content,and they are in direct proportion to(w-w0).At last,a measuring method of coefficient of moisture swelling is established by adopting lateral restricted nonloaded swelling experiment in the light of expansive soils in Ningming section of Nanning-Youyiguan road,and an advice is put forward for embankment construction of the road.