Investigation into mechanical behaviour of loess-wheat straw mixtures

Most residential houses in Loess Plateau of Northwest China have been built five decades ago. The wheat straw retrieved after crop harvesting has always been mixed with the loess to construct house walls. In spite that the extreme climate has already caused a series of extensive natural hazards (e.g., earthquake), the residential houses are well functioned until nowadays. This unique phenomenon drives this study to investigate the mechanical behaviour of the mixture of loess and wheat straw. Thus, uniaxial compressive strength tests and strain-controlled and stress-controlled direct shear tests are implemented on the loess-wheat straw mixture specimens. By adding the wheat straw to the specimens, the failure mode is transfers from the "shear failure" to the "ductile (barrel-shaped) failure" under uniaxial compression loading conditions. Compared to the loess specimens, the loess-wheat straw mixture specimens demonstrate its superior ability of withstanding larger shearing stresses as subjected to similar shear displacements. The gained insights guide the design of upcoming sustainable infrastructures. © 2019 7th Asia-Pacific Conference on Unsaturated Soils, AP-UNSAT 2019. All rights reserved.