基于生物胶复合黏土的陡坡客土基材抗剪强度试验研究

Experimental Study on Shear Strength of Guest Soil Substrate with Steep Slope Based on Biological Gum Composite Clay

为研究生物胶对陡坡客土基材抗剪切特性的影响,通过室内直剪试验探究了黏土剪切力学特性随生物胶含量和养护时间的变化规律,并采用扫描电镜方法对其强化机理进行了讨论.结果表明,天然刺槐豆胶作为生物胶添加剂可以大幅提升黏土的抗剪强度,其抗剪强度随着刺槐豆胶含量的增加而增加,最高可达到243.33 kPa;然而,刺槐豆胶含量由1.5%增加至2%时,黏土的抗剪强度仅提升2.1%,考虑到经济因素,因此本研究用刺槐豆胶加固黏土的最优含量是1.5%;此外,养护时间与试样抗剪强度呈正相关,养护7 d后,试样抗剪强度可达123.57 kPa.养护龄期越长,刺槐豆胶、水和土颗粒越能够充分结合.刺槐豆胶的掺入增强土粒间胶结作用,填补土颗粒之间的孔隙,增强了颗粒间的胶结,进而增加土体黏聚力,提升土体宏观剪切性能.

To investigate the effect of biogum on the shear properties of the guest soil on steep slopes,the variation pattern of shear mechanical properties of clay with the content of biogum and curing time was explored by indoor direct shear tests,and the strengthening mechanism was also discussed using the scanning electron microscopy(SEM).The results show that locust bean gum as a biogum additive can greatly improve the shear strength of clay.The shear strength of clay increases with the increase of locust gum content,and the maximum shear strength can reach 243.33 kPa.However,the shear strength of clay is only increased by 2.1%when the content of locust bean gum is increased from 1.5%to 2%.Considering the economic factors,the optimum content of locust bean gum to strengthen the clay is 1.5%.In addition,the curing time is positively correlated with the shear strength of the specimen,and the shear strength of the specimen can reach 123.57 kPa after curing for 7 d.The longer the curing time,the better the combination of locust bean gum,water,and soil particles.The addition of locust bean gum can strengthen the cementation between soil particles,fill the pores between soil particles,and improve the cementation between the particles,thereby increasing the cohesion of the soil and improving the macroscopic shear properties of the soil.