| Geotextile reinforced rubber sand mixture composite isolation cushion,That is put rubber sand mixture into the geotextile bag,on the one hand,rubber sand mixture is a bulk material,horizontal stiffness and vertical modulus is small;on the other hand,As the rubber sand under put into the geotextile bag,under the effect of vertical pressure,the geotextile bag will produce greater tension,thereby enhancing the vertical carrying capacity,increase the compression modulus,reduce the vertical settlement.In order to provide the theoretical guidance for the geotextile reinforced rubber sand as the isolation cushion further,this paper focuses on the carrying capacity and dynamic characteristics of the geotextile reinforced rubber sand mixture.A series of studies were conducted through the large-scale simple-shear test,the main content of the study are as follows:1、Four kinds of geotextile reinforced rubber sand mixture with different rubber contents were subjected to large-scale single-shear test under 3 kinds of consolidation pressures.The variation of hysteresis curve,stress-strain curve and damping ratio curve of six kinds of shear displacement amplitude are compared and analyzed.The results show that the shear modulus of geotextile reinforced rubber sand mixture is reduced with the increase of the rubber content.The geotextile reinforced rubber sand mixture has a variable horizontal stiffness and realistic possibilities as the foundation.The damping ratio increases first and then increases with the increase of shear strain,and the critical value of shear strain is about 0.014.The damping ratio decreases with the increase of rubber content,and the decreasing trend decreases with the increase of rubber content,and the critical value of rubber content is about 30%.2、A large-scale single-shear test was carried out on the geotextile reinforced rubber sand mixture with different placement methods,two rubber contents,three vertical consolidation pressures and six shear displacement amplitudes were set up.The influence of the placement method on the dynamic shear modulus and the damping ratio is compared and analyzed.The results show that the dynamic shear modulus of the vertical placement is the smallest,and the maximum longitudinal position is the maximum;In the case of rubber content of 20%,the vertical placement of damping curve is highest,followed by the laterall placement,the lowest is vertical placement,the damping ratio curve of 30% from high to low: vertical,longitudinal,lateral;Generally,the damping ratio follow-up shear strain decreases first and then increases,the critical value of shear shear strain is about 0.014.3、A large-scale single-shear test was carried out on different pre-installed geotextile reinforced rubber sand mixture,to determine the best pre-tension of the geotextile bag.Three kinds of pre-tension were set up,and three kinds of pre-tension The dynamic shear modulus curve and the damping ratio curve and the destruction of the shape after cycle shear and so on.The results show that the smaller the pre-tension of the geotextile bag,the smaller the damage degree of the soil bag.The shear modulus decreases with the decrease of the pre-tension,and the change between the three and four layers is not significant;the decrease of the pre-tension will cause the damping ratio to increase,and the geotextile reinforced rubber sand mixture will play its energy dissipation effect better;the best pre-tension of geotextile reinforced rubber sand mixture is the three layers of geotextile bag corresponding to the pre-tension.The optimum bagging capacity is 60%.4、Through the comparative analysis of the geotextile bags reinforced rubber test and the geocells reinforced rubber test data,the geocell increases the horizontal shear modulus and reduces the rubber damping ratio.The dynamic shear modulus of geotextile bags is the least,and the damping ratio is the biggest,it is conducive to play the vibration effect.In this paper,the dynamic characteristics and vertical deformation characteristics of the composite cushion of geotextile bags reinforced rubber sand mixture are studied by large-scale single-shear test,which will establish a theoretical foundation for the future study of the dynamic characteristics of rubber sand and the reinforcement method of rubber sand. |
