海绵城市消落带土体结构与适用植被根系固土强度试验研究

Experimental Study on Soil-fixation Strength of the Sponge City Riparianzone Soil and Suitable Plant Roots

通过植被与河道边坡的有效组合,可实现海绵城市河道治理工程生态环境效益最大化,植被根系对河道消落带土体的加固效果直接影响河道治理效果。为此,依托绵阳市小枧城市生态湿地公园河道工程,选取河道消落带土体及狗尾草进行室内三轴固结不排水剪切试验研究。研究结果表明,当含根量较小时,根系对消落带土体强度无促进作用,随着剪切位移的增大,含根系的消落带土体剪切应力增大,表现出明显的根系加筋效果;最大、最小围压和含根量下,随着干湿循环次数的增加,消落带土体剪切应力逐渐减小,干湿循环次数对土体强度的影响较大;含根量越高,消落带土体黏聚力越大;随着干湿循环次数的增加,消落带土体黏聚力逐渐降低;含根量不为0时,随着含根量的增大,消落带土体内摩擦角逐渐增大;随着干湿循环次数的增加,消落带土体内摩擦角呈小幅波动变化趋势。

Through the effective combination of plants and river slopes, the ecological environmental benefits of sponge city watercourse regulation projects can be maximized. The reinforcement effect of plant roots on the riparianzone soil of watercourse will directly affect the effect of watercourse regulation. Relying on the watercourse regulation project of Xiaojian Urban Ecological Wetland Park in Mianyang, this paper selected the riparianzone soil and setaria to carry out the indoor triaxial consolidated undrained shear tests. With the increase of shear displacement, the shear stress of riparianzone soil with plant roots increases, which shows obvious root reinforcement effect. Under the maximum confining pressure, minimum confining pressure, maximum root content and minimum root content, with the increase of the number of dry and wet cycles, the shear stress of riparianzone soil gradually decreases, which shows that the number of dry and wet cycles has a greater impact on the soil strength. The cohesion of riparianzone soil increases with the increase of root content. With the increase of the number of dry and wet cycles, the cohesion of riparianzone soil gradually decreases. When the root content is not 0, with the increase of root content, the internal friction angle of riparianzone soil gradually increases. With the increase of the number of dry and wet cycles, the internal friction angle of riparianzone soil in the fluctuating zone fluctuates slightly.