The Applied Research Of The High Pressure Jet Grouting Pile And Jet Grouting Anchor Combined Form In The Soft Site

In recent years, the foundation pit engineering accidents occurred frequently inmany cities in our country, most of which are deep foundation pit engineeringaccidents, more than one over ten of the total in deep foundation pit engineering. whatis more, the high accident rate in soft soil area of underground water level is anastounding30%. Soft soil due to the large compressibility, low permeability, lowshear strength and rheological property, belong to the foundation pit engineering inpoor soil, higher requirements on the performance of the supporting structure,especially in some high water level of the soft soil areas, in addition to supporting soilretaining, precipitation, water drainage, water blocking water are also particularly aheadache to most engineers.In reference to a large number of foundation pit engineering accident statistics,and combined with the present situation of foundation pit supporting engineering insoft soil area of research and scheme comparison, this paper mainly studies the depthof excavation in soft soil area in6~14m of foundation pit engineering design andconstruction scheme, on the premise of ensuring safety. This article research adoptedthe theory analysis combined with the engineering practice, the method of combiningthe high pressure jet grouting pile reinforcement and jet grouting anchor ropecombined support system of the application of a deep foundation pit engineering inzhengzhou, using theoretical analysis and calculation and field test research andengineering measurement for its design calculation, construction process andsupporting effect analysis and evaluation. According to the stress nephogram ofsupporting structure in engineering dangerous section puts forward the forecastingand analysis, in order to provide reference for design and construction of similarprojects. Specific research contents and relevant conclusions are as follows:1.This paper briefly describes the working mechanism of high-pressure jetgrouting method, the mechanism of high pressure jet grouting pile is analyzed, and theinfluence factors of pile, the engineering mechanical properties of the high pressurejet grouting pile is studied, some related conclusions, so as to provide guidance andreference for the similar projects.2.Focuses on the bending capacity of the high pressure jet grouting pilereinforcement, by establishing the mechanical model of steel shapes and cement-soil, analyses its constitutive relation, the loads is obtained, the high pressure jet groutingpile reinforced at every stage of the load-deformation characteristics and the relevantmechanical parameters calculation formula.3.Analyzed the reinforcement, the overall bending stiffness of the high pressurejet grouting pile, soil and water on the stiffness contribution of the whole structure,found that the reinforcement of the high pressure jet grouting pile bending stiffnessand internal force of structure has a close relationship; and it is concluded that thetreated water mud with high pressure grouting technology to improve the steelstructure stiffness has a certain margin, far more than5%of the proportion, and thegeneral steel cement wall, compared to the contribution of water in the soil stiffnessafter high pressure grouting process, the contribution rate of treated water dirt on thewhole stiffness has obvious improvement.4.Combined with practical engineering of jet grouting anchor cable are analyzedin theory, design calculation and field test, the rotary spray anchor cable is obtainedmore conventional anchor cable construction technology optimization, morereasonable, which can effectively avoid the conventional anchor grouting is not full,easy to reducing, broken pile and unable to overcome the defects such as process ofsettlement, the pulling force is usually2~3times of conventional anchor cable, caneffectively reduce the foundation pit slope Angle, slope to reduce support density,strengthen the slope supporting anchoring quality of anchor cable and other usefulengineering important conclusions.5.Use of foundation pit supporting professional analysis software, for the highpressure jet grouting and pile reinforcement of jet grouting anchor combined supportsystem, analyzed the supporting effect of the overall research obtained somebeneficial to guide the design, construction.6.Put forward the high pressure jet grouting and pile reinforcement of jetgrouting anchor combined support system, is applied to the high water level of thefoundation pit in soft soil area, and in the practical engineering inspection, thesupporting system of the application effect is good, can provide useful reference forsimilar projects.