Study On Reinforcement Effect Of SH-solidified And Hemp Fiber-reinforced Earthen Sites Soil

There are many kinds of deteriorations in the earthen sites,and the sapping of wall bottom is one of the most common deteriorations in the earthen sites.At present,the main repairing methods are tamping backfills or masonry backfills.However,in these reinforcement methods,the tension stress between the upper and lower walls caused by consolidation settlement after tamping,or the shear stress and tension stress in the inner part of tamping due to the existence of the upper pressure and the free surface were not taken into account.These forces reduce the stability of the wall.At this point,if the consolidation agent and reinforcement materials are added to the rammed earth,the compressive and tensile properties of the rammed earth will be improved,which is helpful to improve the stability and integrity of the wall.In this paper,the corrosion area at the bottom of the earthen sites was taken as the research object,and the reinforcement material SH and the hemp fiber reinforced material are applied.Using the method of the orthogonal experiment design,the experiment was designed and analyzed with the variables of three factors,namely,the solid content of SH,the length of hemp fiber and the amount of reinforcement,with five levels.At the same time,the solid content of SH was selected as 0.5%,and the orthogonal test design was carried out on two factors including the length of the hemp fiber and the amount of reinforcement,with three levels,followed by the unsaturated freeze-thaw cycle test,dry-wet cycle test and disintegration test.The following conclusions were drawn:(1)The solid content of SH had the greatest influence on the compressive strength and tensile strength of the samples,followed by the amount of reinforcement,and finally the length of the hemp fiber.The relationship of reinforcement with the compressive strength and tensile strength is different.The greater the reinforcement,the greater the impact on the compressive strength,and the smaller the impact on tensile strength,meaning that the amount of reinforcement is positively correlated with the compressive strength and negatively correlated with the tensile strength.With the increase of the reinforcement amount,the failure forms of the samples changed from the brittle shear failure to the plastic failure.It is determined that the optimum combination occurs when the solid content of SH is 0.7 %,the length of the hemp fiber is 1 cm,and the amount of reinforcement is 0.2 %.(2)SH can significantly improve the samples resistance to the freeze-thaw,drywet and disintegration,but the changing trends of the physical and mechanical properties of the samples are different.At the same time,when the length of hemp fiber and the amount of reinforcement are not same,the change of the quality and strength also shows certain regularity.(3)The selected hemp fiber is suitable in length and reinforcement,and after the SH solidification,the soil shows high mechanical strength and aging resistance.When the selected hemp fiber is suitable in length and reinforcement,the soil shows high mechanical strength and aging resistance after the SH solidification.The effect of SH solidification and hemp fiber reinforcement can significantly improve the connectivity,stability and safety of the soil of earthen sites.