Study On The Performance And Dehydration Curing Treatment Of Large Diameter Pile Project Waste Mud

In recent years,with the continuous increase of infrastructure construction efforts,more and more waste mud is generated during the construction of pile foundation projects.In this research,the performance of waste mud,the damage of soil composition on mud performance,and the influence of mud composition on soil physical and chemical properties are analyzed;the flocculation and dewatering principles of organic and inorganic materials are tested,a flocculation and dewatering treatment formula with high applicability is developed;and the compound curing agent formula of mud curing body is further studied.The main research results are as follows.（1）Some performance indexes of the waste mud have exceeded the qualified range and have a large impact on normal construction.Soil composition,chlorite,mica and quartz three minerals accounted for about92%,soil composition mainly through changing the solid phase content of the mud to cause damage to the mud system.The solid phase content is controlled between 0 and 10%,which has a small effect on the rheology of the mud.However,after the waste mud content increased to 40%,several physicochemical properties of the soil were severely damaged.（2）The natural sedimentation ability of waste slurry without adding flocculants is poor.Among the three organic flocculants,the flocculation effect was ranked as APAM>NPAM>CPAM.the dewatering efficiency of APAM flocculant is about 27%～37%higher than the other two.The mixing ratio of APAM alone is 0.2‰（g/m L）,and the maximum settling volume is 15.2 mm within 60 min.The flocculation effect of inorganic polymers was ranked as PAC>PAFC>PASD,where PAC had the best flocculation and sedimentation effect at a mass concentration of about 1%,with a maximum settling height of 10.2 mm within 60 min.（3）The formula of compound flocculant is:0.15APAM+1.0PAC（g/L）,compared with the single organic flocculant,the flocculation treatment effect is improved by about 1 time.The formula of compound dewatering curing agent is:lime dosing 6%;water glass dosing10%～15%;calcium chloride dosing 1.5%～2%;epoxy resin dosing 5%,where the ratio of epoxy resin to APAM is 1.0.The formula can reduce the water content of mud from 120%to about 36%in a shorter time,and the collapse height of mud curing body is controlled below 2 mm.And field application and potting experiments proved the feasibility of this formulation.（4）Through single-factor tests,detailed analyses of material admixture,curing age,material type and pre-strength ratio were carried out,and the admixture range of each material was derived.HQS and micro-silica powder have a greater effect on the enhancement of the strength of the cured body in the early stage,while fly ash and gypsum can play a greater role in the later stage.When the water content of waste slurry exceeds 250%,it is not suitable for direct curing treatment,the water content is controlled below 150%;and the water-cement ratio required for curing waste slurry is appropriate between 1.5 and 2.1,especially in about 1.8 when the curing treatment effect is the best.（5）In the orthogonal test,the best ratio is A₃B₂C₄D₃E₁ for group 10,and the uniaxial compressive strength of the cured body reach 3.4 MPa.The formula of the compound curing agent is:cement proportion:27%;HQS proportion:10%;micro-silica powder proportion:20%;fly ash proportion:18%;gypsum proportion:25%,and the admixture of the compound curing agent is 56%（g/m L）.The research results of this paper have certain guiding significance for the treatment of field engineering slurry and are of reference value for promoting the development of technology in this field.