Study On Mechanical Properties Of Compacted Stabilized Soil Mixed With Rubber Chips(CSSRC)

Compacted stabilized soil mixed with rubber chips(CSSRC)is a mixed soil with adjustable density and strength,which is made of soil,waste rubber chips,cement and water after being fully mixed and stirred.Its compaction characteristics,strength characteristics and deformation characteristics will be affected by the physical and mechanical properties and ratio of various raw materials.In this paper,laboratory experiments were used to test the effects of various raw materials on the physical and mechanical properties of CSSRC,and the theoretical analysis was used to discuss the mechanism of the effects of each component material on the strength and deformation characteristics of the mixed soil.The main research contents and achievements of this article include:(1)The influence of the content of rubber chips and cement on the compaction performance of CSSRC was tested,and the variation law of dry density and moisture content of the mixed soil was studied.It was found that there was an optimal moisture content of CSSRC to make it reach the maximum dry density whether it was standard light compaction or standard heavy compaction.The maximum dry density of CSSRC under compaction decreases linearly with the increase of tire particle content.The minimum dry density is only1.24g/cm³,which is 27%lower than that of pure soil.When the content of rubber chips is large,it is easier to increase the moisture content than the compaction work to maximize the dry density of CSSRC.The optimum moisture content of CSSRC under compaction also decreases linearly with the increase of tire particle content.(2)The compression properties of CSSRC under the condition of side limit are tested.It is found that the compression strain?and porosity change rate(e₀-e)/e₀ of CSSRC increase linearly with the increase of tire particle content U.When the vertical stress is 0.5MPa?P?4MPa,the stress-strain relationship of CSSRC under lateral compression changes linearly in the semi logarithmic coordinate system.In the e-lgp curve,the void ratio of CSSRC decreases linearly with the increase of vertical stress,and the slope of its straight line becomes the compression coefficient C_cof CSSRC,which is close to a constant,and does not change with the change of p,rubber chips and cement content.(3)The unconfined compressive strength of CSSRC was measured at different ratios,and the strength and deformation characteristics of CSSRC were analyzed.It was found that when the content of rubber chips was low,the unconfined compressive strength of CSSRC samples could be improved more easily by heavy compaction than by light compaction,and vice versa when the content of rubber chips was high.The unconfined compressive strength of CSSRC increases gradually with the increase of cement content.The unconfined compressive strength of light compacted samples with rubber chips can reach up to 1100kpa.When the rubber chips content is more than 10%,the influence curve of the rubber chips content on the unconfined compressive strength of CSSRC samples decreases linearly.The unconfined compressive strength of light compacted samples with 55%rubber chips content is 569k Pa?(4)The effects of rubber chips and cement on the shear properties of CSSRC were studied.It was found that the shear strength of CSSRC samples increased linearly with the increase of vertical pressure,which was in accordance with the shear strength formula of soil.The cohesion and internal friction angle of CSSRC gradually decrease with the increase of tire particle content,because the addition of rubber chips reduces the original cohesion and sliding friction of the sample;the cohesion and internal friction angle of CSSRC gradually increase with the increase of cement content,because the addition of cement improves the curing cohesion and bite friction of the sample.(5)It is found that the expansion of CSSRC increases with the increase of tire particle content and decreases with the increase of cement content.The swelling capacity of CSSRC sample increases linearly with the increase of tire particle content after soaking for 4 days and nights.The load ratio of CSSRC decreases with the increase of tire particle content,but the decrease is not significant.With the increase of cement content,the load ratio of the sample with 5%cement content is 80%higher than that of the sample with 1%cement content.Through the study of the physical and mechanical properties of CSSRC,it is concluded that CSSRC can be used in geotechnical engineering,which can improve the density and strength characteristics of fill,and at the same time can solve the problems of land occupation and environmental pollution caused by other treatment methods of waste tires.