重塑膨胀岩土微变形条件下膨胀力试验研究

 通过对南宁膨胀性泥岩重塑土样进行变形量分别为0，0.2，0.5和1 mm的微变形膨胀力试验，分析膨胀力的主要影响因素，建立膨胀力与干密度、初始含水率双因素之间关系，研究微变形条件下膨胀力变化机制。结果表明：(1) 零变形时，膨胀力随干密度增大呈指数形式增大，并与初始含水率呈幂函数关系。(2) 微变形时，膨胀力随变形增大而衰减明显，在干密度大、初始含水率低时衰减幅度较大，反之较小；在干密度及初始含水率一定时，微变形膨胀力随着变形率增大而呈指数衰减。(3) 微变形与零变形膨胀力之比随变形率增大而呈指数减小，当变形率为1%，2.5%和5%时，微变形膨胀力与对应零变形膨胀力之比分别为75%，55%和35%。

TEST RESEARCH ON EXPANSIVE FORCE UNDER SMALL DEFORMATION OF REMOLDED EXPANSIVE ROCK AND SOIL

A series of expansive force tests of small deformation as 0，0.2，0.5 and 1 mm were conducted on the remolded samples of expansive soil in Nanning to obtain the key influence factors of the expansive force. A formula of the expansive force with initial water content and dry density was given；and small deformation expansion force variation law was analyzed. The results show that：(1) When the expansive force test shows non-deformation，the expansive force increases exponentially with dry density increases and presents a power function relation with the initial water content. (2) Test of small deformation shows that the expansive force attenuates obviously with the deformation increases；in the condition of high dry density and low initial water content，the amplitude of attenuation are larger；otherwise smaller. Under constant dry density and initial water content，the small deformation expansive force exponentially attenuates with the deformation rate increases. (3) The expansive force ratio of non-deformation and small deformation decreases exponentially with the increase of deformation rate；when the deformation rate is 1%，the ratio of small deformation expansive force to non-deformation expansive force is 75%；this ratio is 55% when the deformation rate is 2.5%；and this ratio is 35% when the deformation rate is 5%.