粉煤灰改良膨胀土力学特性试验

Experimental Study on Mechanical Properties of Expansive Soil with Fly Ash

通过无侧限抗压强度试验及直剪试验,研究不同粉煤灰掺量条件下(0、8…%、15…%、20…%、25…%、30…%、40…%),改良膨胀土的力学特性变化规律,研究结果表明:随着粉煤灰掺量增加,膨胀土无侧限抗压强度及抗剪强度参数呈现先增加后减小的趋势,并且得到粉煤灰改良膨胀土的最优掺量为30…%;在最优掺量条件下,改良膨胀土力学参数与粉煤灰掺量呈现指数函数变化关系;粉煤灰显著提高膨胀土无侧限抗压强度及粘聚力,最大增幅分别为0.44…MPa、0.65…MPa,但粉煤灰掺加对于内摩擦角影响较小。因此,可以认为粉煤灰对膨胀土力学强度产生显著改良,较好的满足工程强度要求。

Through unconfined compressive strength test and direct shear test, the mechanical properties of the expansive soil was studied under different fly ash contents（0, 8%, 15%, 20%, 25%, 30% and 40%）. The results show that with the increase of fly ash content, the unconfined compressive strength and shear strength parameters of expansive soil first increases and then decreases, and the best mixed fly ashmodified expansive soil amount is 30%; under the optimal dosage conditions, the mechanical properties of modified expansive soil and fly ash content showed an exponential function variation; fly ash significantly improves the unconfined compressive strength and cohesion of expansive soil, the maximum increases 0.44 MPa、0.65 MPa respectively, but less for the internal friction angle. Therefore, it can be considered that the fly ash has a significant improvement on the mechanical strength of expansive soil, which better meets the engineering strength requirements.