麦秸秆加筋滨海盐渍土的抗剪强度与偏应力应变

Triaxial shear strength and deviatoric stress-strain of saline soils reinforced with wheat straws

与土工格栅加筋土不同,植物纤维土在加筋补强机制与抗变形性能上具有自身的特点,这可通过纤维土的三轴UU压缩试验进行研究。由麦秸秆纤维加筋滨海盐渍土的三轴抗剪强度及其偏应力应变曲线表明:①与盐渍土相比,麦秸秆纤维土的黏聚力大幅提高,内摩擦角的增幅很小。②加筋长度比0.16质量加筋率0.25%为适宜的纤维加筋条件。③纤维土的偏应力应变曲线与盐渍土的变化形式相近,均呈应变硬化型。轴向应变较小时,加筋长度比和质量加筋率对主应力差的影响较小,纤维加筋作用微弱;随轴向应变的增大,两者的影响加大,纤维加筋作用才逐渐发挥出来。④相互交织的麦秸秆纤维对土形成了空间约束作用,使得4个围压的纤维土的破坏应变均大于盐渍土的。麦秸秆纤维加筋不仅提高了土的黏聚力,还增强了土的抗变形能力。

Comparing with soils reinforced with geo-cells, the special properties of texsoil （soils with plants fibers） were studied by means of triaxial shear test, with regard to the reinforcement mechanism and deformation-resistant characteristics. The results indicate ： （ 1 ） the cohesion of texsoil is larger than that of saline soil, while the friction angle is only slightly larger than that of saline soil; （2） the suitable reinforced length ratio and reinforced mass ratio are 0.16 and 0.25% , respectively ; （3） the deviatoric stress-strain curve of texsoil is similar to that of saline soil, and both exhibiting strain-hardening; and （4） intersecting wheat straws contribute confinement to the soil in all directions, thus making the failure strain of texsoil larger than that of saline soil under full confining pressures. In general, the study can prove that the cohesion and the deformation-resistance of soil can be enhanced by the reinforcing fibers of wheat straws.