Experimental Study On Mechanical Properties Of Foamed Particle Light Weight Soil Mixed With Silt

With the quick development of national economy, there are more and more civil engineering actions. Base facilities, such as roads and bridges, are built in the south-east coastland, there are a lot of problems that can't be solved by conventional means, such as big settlement, un-uniform settlement and long time settlement of soft-soil foundation. In addition, with the continued shortage of natural resources and emphasizing on the environment protection, technologies to generate silt and waste plastic into resources are paid more attention to.Light weight soil is a kind of soil that relieved weight in unit volume, and is a man-made new type geo-material, and it has many advantages, such as light weight property, self support property, endurable compression property, durability, resiliency, easy construction property, heat proof property, saving economy property, environmental protection property and so on. Base on light weight property and easy construction property, light weight soil is a new type filling material which can make good use of dredged silt, engineering waste soil, factory waste and so on. Foamed particle light weight soil mixed with silt is prepared with silt of Wenzhou bay in the East Sea as base soil, EPS particle as light weight material, and cement as solidifying agent. Base on laboratory test, its mechanical properties are researched as follows:(1)Sample preparation and curing method of foamed particle light weight soil mixed with silt have been studied, the technology which treat silt by solidification treatment and light weight treatment in force is full feasible.(2)Density of light weight soil is mainly affected by EPS mixing radio according to density test, others can be ignored in practical engineering.(3)Uniaxial compressive strength of light weight soil is mainly affected by cement mixing radio, EPS mixing radio, water content and age according to unconfined compressive strength test.(4)Main advantages of light weight soil are as follows: light weight property, high strength property, and strength can be adjusted by changing density. Two kinds of recipe formulas are given in the paper: fitting method of linear relation and fitting method of exponential relation.(5)Uniaxial stress-strain property and triaxial stress-strain-porewater pressure property, which are affected by cement mixing radio, EPS mixing radio, water content and age, are analyzed in the paper. Uniaxial stress-strain curve is hump curve, which belongs to strain-softening type, and it can be divided into four stages: pore compression stage, elastic deformation stage, plastic yield stage, destructive afterward stage. CU stress-strain curve has three properties: nonlinear, strain-softening and strain-hardening, strength increasing with confining pressure increasing. Porewater pressure has three representations: one is porewater pressure first increases, then decreases; the second one is porewater pressure increases with axial strain increasing; the last one is porewater pressure increases to a certain stable value with axial strain increasing at last.(6)Uniaxial stress-strain curve and triaxial stress-strain curve are simulated by Duncan-Chang hyperbolae model, which can reflect nonlinear property well and provide some references for building constitutive model and choosing engineering design parameters.(7)Relations between uniaxial compressive strength and deformation modulus, uniaxial compressive strength and destructive strain, uniaxial compressive strength and yield limit under uniaxial compressive condition are studied so that top load, yield stress, and deformation controlling can be ascertained according to uniaxial compressive strength; relations between confining pressure and deformation modulus, confining pressure and yield limit under triaxial compressive condition are studied so that foundation settlement and deformation controlling can be estimated.(8)Base on CU test, maximum stress difference standard should be adopted for failure choosing value standards of foamed particle light weight soil mixed with silt, then referring to failure envelope, it is accordance with Mohr-Coulomb failure criterion. There are two types of shearing strength envelope: broken line type and linear type. Shearing strength parameters(c,Φ) are influenced mostly by cement mixing radio, EPS mixing radio.(9)Failure modes and failure shapes under uniaxial compressive condition and triaxial compressive condition are studied, and the principle of cracks expanding to shear failure is explained reasonably.