圆砾改良膨胀土膨胀性试验研究

针对陕南旬阳地区某电厂工程在地基处理过程中遇到的膨胀土问题,结合场址附近圆砾资源丰富的地质条件,提出了一种新的改良方法——在膨胀土中掺入圆砾.根据土工试验规程进行重型击实试验,分别按照掺加圆砾比例为0%、20%、30%、40%、45%和55%开展试验.研究结果表明:改良试样的最大干密度从1.84g·cm-3提高到2.05g·cm-3,最优含水量从18.76%降低到11.32%;对改良试样进行膨胀量试验,掺加圆砾比例为45%时膨胀性改良效果最好,浸水膨胀达到稳定的时间约为600min.而未掺加圆砾的试样在2 160min还未达到膨胀稳定状态.

Experimental Study on Expansive Soil Improved by Circular Gravel

Aiming at expansive soil problem of a power plant project in Xunyang area encountering in foundation treatment process ,considering the geological conditions of circular gravel resource rich near sites ,a new method-mixing the circular gravel with expansion soil is put forward .The samples with 0% ,20% ,30% ,40% ,45% and 55% circular gravel are carried out the heavy compaction test in accordance with the rules of soil test .It is found that the maximum dry density of modified soil increased from 1 .84 g · cm -3 to 2 .05 g · cm -3 ,the optimum moisture content decreased from 18 .76% to 11 .32% . The swelling capacity test of the modified samples showed that expansion modification effect of the soil mixed with gravel ratio up to 45% is the best .The swelling stable time is about 600 min ,while the samples without circular gravel has not yet reached the steady expansion state at 2 160 min .