Study On The Pile-forming Quality And Analysis Of Stess Characteristics Of Cement Mixing Pile Grid Wall In Soft Soil

China has widespread soft soil on the coasts,plains,and inland lakes and rivers.Most of the soft soils are distributed in China’s economically developed and densely populated areas.Soft soil has characteristics of high compressibility,high water content,high sensitivity,low shear strength,etc.Engineering accidents such as uneven settlement of buildings and collapse of foundation pits often occur in the engineering construction above soft soil.As an effective form of soft ground treatment,cement mixing piles are widely used in various soft soil projects.The cement mixing pile grid wall is characterized by simple construction,less disturbance and low cost,and it is very common in the foundation pit project where the excavation depth is not more than 7 meters in the soft soil area.At present,most of our country studies the cement mixing pile grille wall analogy to the traditional gravity retaining wall,but there is a big gap between the cement mixing pile wall and the traditional gravity retaining wall,with uneven wall material,too deep into the soil,and the body width is too wide and so on.Domestic research on the change of the strength of materials with different depths in the wall of the cement mixing pile grid wall and the distribution of the external load on the wall and the soil between the piles are less.Therefore,this paper relies on the Lishiwan ship lock engineering of CCCC Fourth Harbor Engineering Co,Ltd,and count the pile-forming quality of cement mixing piles at different depths and analyzes the stress characteristics through on-site coring.In addition,the finite element numerical simulation method is used to study the mechanical properties of the cement mixing pile grid wall.The main research contents and conclusions of the article are as follows:1.In the project construction site,several sets of cement mixing pile test trials were conducted to analyze the causes of the poor quality of cement mixing piles in deep soft soil,and proposed improvement methods.The coring research of different depths of the improved cement mixing piles was conducted to investigate the unconfined compressive strength values of the cement mixing piles at different depths.The relationship between the unconfined compressive strength and the depth of the cement mixing piles was obtained.2.Make a unified analysis of the on-site statistics of the strength of cement mixing piles and the results of previous laboratory experiments.The relationship between the soil mechanics parameters and the depth of the cement mixing pile is analyzed and studied.3.Numerical simulation of cement mixing piles was carried out using Midas GTS finite element software referring to the engineering drawings of the project of the Lianshiwan Ship Lock.Exploring the stress characteristics of the cement mixing pile grid wall under different loading modes.Simulating of the distribution of soil pressure on the cement mixing pile grid wall and tipping and slip characteristics during the excavation of foundation pit in soft soil area.Providing a reference for similar projects in the future.