Study On The Complex Grouting Technique In Foundation Reinforce

Technique of composite grouting is a new type grouting technique which make still pressure technique and high pressure spin spray technique unite according to sequence in order to exert their advantage. It can fully exert each advantage and get over each disadvantage about still pressure technique and high pressure spin spray technique, thereby attain the maximal applicability stratum range and best reinforce effect, and assure succeed rate and security of reinforce.1.The paper detailed study the characteristic, construct order, serum material, major construct process parameter, major construct equipment of technique and the construct process of composite grouting. At the same time,the paper in-depth discuss the reinforce foundation operation mechanism of technique of composite grouting, including spray incise action of high pressure spray flow to soil, mill metathesis concretion action, and penetrate, split, crush action of serum to soil, etc.2.The limit pressure of spherical cavity expansion is given by the law of conservation, in which the volume change of spherical cavity is balanced with the compression of granular soil and the energy given out from spherical cavity expansion is absorbed by the volume change and shear strain caused in granular soil. The stress-strain-volume change relationships and nonlinear strength behaviors of granular soils under high stresses are described. This method can be used to estimate the resistance of compression grouting. The process of analysis shows that the limit pressure is determined by the characteristics of stress-strain-volume change relationships and strength of granular soil, and has no concern with the pressure of superstratum. The theoretical values agree with the measured values from the field test.3.On the bases of the plastic mechanical mechanism and the large strain, the early phase of fracture grouting is regarded as the question of cavity expansion in infinite soil. The stress distribution due to the cavity expansion in soil is considered as two zones. The deformation following little deformation in elastic zone and large-deformation in plastic zone is taken into consideration. The initial fracturing grouting pressure is the limited expansion pressure and the second fracture grouting take place when the large and small stress of soil is conversion. On the bases of the stress equilibrium equation and continuous boundary condition of stress and deformation, the stress distribution in the elastic-plastic zones, the terminal plastic zone radius and fracturing grouting pressure are obtained. According to the compassion, the result of the present theory is very near to that of the engineering practice.4. On the assumption that the grouting flow in soil crack accord with H. Darcy law and the last formative crack breadth is even crack breadth, educed the attenuation law of pressure and the crack pervasion along the grouting radium, these conclusion are proved true by making use of numerical analyses method. On the base of the above conclusion, the more grouting bore of the influence is analysesed at the same, and the number and optimization position is deduced, and the grouting pressure, the influence of more grouting bore and diffuse radius is given.5. The paper in-depth study design calculate of composite grouting, design of composite grouting technical parameter.6. The paper study the serum material and prescription of by chamber experiment, study the construct process and key technic parameter by locale simulation test, and study the dispose effect, applicability stratum range and operation mechanism in foundation reinforce by studying practicality project, the paper still study the test of reinforce effect about present building foundation and disfigurement stake of technique of composite grouting.