Research On Design Optimization And Quality Evaluation Technology Of Saturated Silt Soil Slurry Pile In The Lower Reaches Of The Yellow River

The national strategy of the Yellow River proposes to improve the construction of major cross-regional infrastructure systems such as transportation and energy in the Yellow River Basin,and optimize and improve the expressway network in the Yellow River Basin.Saturated silt is an unavoidable foundation soil for highway construction in the Yellow River Basin,because saturated silt in the lower reaches of the Yellow River has undesirable engineering characteristics such as low strength,difficult compaction,vibration and easy liquefaction,effective treatment of saturated silt soil foundation is an important guarantee for highway safety operation.Cement slurry pile has the advantages of low cost,convenient construction,no noise,low pollution,etc.,and is widely used in soft ground treatment,and has achieved good economic and social benefits.However,due to the special engineering characteristics of saturated silt,it is difficult to form piles and poor piling quality when cement slurry spray piles reinforce saturated silty soil foundations,and the quality inspection of composite foundation reinforcement is inefficient,time-consuming and laborious,which seriously restricts the construction of expressways in this region.Therefore,it is of great engineering significance to carry out the research on the design optimization and quality evaluation technology of saturated powder soil pulp spray pile in the lower reaches of the Yellow River.With the support of the key research project "Research on Design Optimization and Quality Evaluation Technology of Saturated Powder Soil Slurry Pile Spray Pile in the Lower Reaches of the Yellow River",and relying on the construction project of the West Ring Section of the Second Ring Road of Jinan Ring Expressway,the reinforcement mechanism,reinforcement effect and quality evaluation of cement slurry pile composite foundation were systematically studied through theoretical calculation and analysis,numerical simulation,indoor test and field test.The main research contents and achievements are as follows:1、Based on the engineering characteristics of saturated silt in the lower reaches of the Yellow River,based on the reinforcement mechanism of cement slurry pile composite foundation,indoor tests were used to summarize and explore the influence of cement content,curing age,water-cement ratio and other parameters on the unconfined compressive strength of cement soil.At the same time,PLAXIS 2D software was used to establish a numerical simulation model of saturated silt cement slurry pile spray composite foundation,and the effects of different pile length,pile strength and pile spacing on the deformation of the composite foundation were analyzed,and the design parameters and construction technology of cement slurry pile injection composite foundation were optimized.2、The transient surface wave nondestructive testing technology is introduced,and the diversified evaluation of the reinforcement quality of the composite foundation of cement slurry blast pile is realized through the calculation of Rui Lei wave inversion,and the empirical formula for calculating the bearing capacity of pile body and composite foundation bearing capacity of Rui Lei wave velocity is given through formula derivation,and the relevant verification is carried out.3、On the basis of fully analyzing the calculation theory of two kinds of foundation settlement prediction and the fusion of Kalman filter data,a mathematical model of settlement prediction was established,and based on this,a settlement prediction software for saturated silt cement slurry pile blast pile foundation was developed to guide the construction of Jinan Da xihuan project section and provide reference for the construction of such projects.