Formula Optimization Research On Soft Soil Solidification In Wuhu

The soft soil in Shenxiang Town,Jiangbei,Wuhu City is marine soft soil with high water content and low shear strength,which is not conducive to urban construction in Wuhu area.In order to make these soft soils meet the actual needs,it is often necessary to cure the soft soil in the area.In this paper,the Box-Behnken method is used to study the solidification treatment of marine soft soil in Shenxiang Town,Jiangbei,Wuhu City through unconfined compressive strength test and theoretical analysis.Therefore,this paper mainly carries out the following work:(1)According to the engineering geological conditions of Shenxiang Town,Jiangbei,Wuhu City and the basic characteristics of marine soft soil,combined with environmental factors and economic factors,granulated blast furnace slag powder(GGBS)is selected to replace cement as curing main agent,calcium oxide and gypsum for external additives.(2)Granulated blast furnace slag powder(GGBS),calcium oxide and gypsum are added in the soft soil to form solidified soil,and the solidified soil is cured for 7days for unconfined compressive strength test.According to the test results,the research range is determined as follows.The blast furnace slag powder(GGBS)is between 8% and 14%,the calcium oxide is between 2% and 5%,and the gypsum is between 2% and 5%.(3)The granulated blast furnace slag powder(GGBS),calcium oxide and gypsum are used as the three influencing factors,and the 7d and 28 d unconfined compressive strength values of the solidified soil are used as the response value.The Box-Behnken method was used to design the test and analyze the interaction between granulated blast furnace slag powder(GGBS)and calcium oxide and gypsum.The optimum ratio is as follows: granulated blast furnace slag powder(GGBS)is 13.26%,calcium oxide(Ca O)is 3.73%,and gypsum is 4.11%.(4)Organic matter affects the solidification effect of soft soil.The main reason is that organic matter can inhibit the formation of gelatinous substances in the soft soil solidification process,and hinder the dissolution of elements such as silicon and aluminum in the soil,thereby suppressing the pozzolanic reaction.Since humic acid is the main component of organic matter in soil and water,this study used humic acidinstead of organic matter in soil to artificially prepare soil with high organic matter content.The humic acid was added to the solidified soil prepared by the optimal mixing ratio.After 7d and 28 d soil conservation respectively,the strength of the solidified soil was observed.It was concluded that with the water content 33.2% and the GGBS 13.26%,Ca O 3.73% and gypsum 4.41% and remaining unchanged,the unconfined compressive strength of the solidified soil decreased significantly with the increase of humic acid content.With the 7d experiment,the strength of the soil is reduced by about 40% while humic acid content is increased to 18%.When the humic acid content is between 3% and 12%,the unconfined compressive strength decreases a little with the increase of humic acid content.When the humic acid content is between 12% and 18%,the unconfined compressive strength of the solidified soilchanges are no longer evident.With the 28 d experiment,when the humic acid content increased to 18%,the strength of the soil decreased by about43.2%.When the humic acid content is between 3% and 12%,the unconfined compressive strength decreases a lot with the increase of humic acid content.When the humic acid content is between 12% and 18%,the unconfined compressive strength of the solidified soil changes are no longer evident.