Abstract:[Objective]To explore the relationship between the characteristics of soil strength and soil pore in the tidal flat reclamation areas under in-situ conditions.[Methods]Taking the soils in different reclamation areas of the coastal tidal flats in Jiangsu Province as the research object,the relationships among soil structure,in-situ soil shear strength (Cu) and sensitivity (St) were analyzed through in-situ vane shear tests and CT scanning technology.[Results]The St values in Binhai(BH)and Rudong(RD)were between 1.3 and 5.4,falling within the range from medium sensitivity(2-4)to sensitivity(4-8). However,for the disturbed soil in these two places,the St values showed no significant changes under different depths and reclamation years. In contrast,the St values of the disturbed soil in Dongtai(DT)varied significantly. The St values in each soil layer were higher than those at BH and RD. Among them,the St value at DT1 was the highest,and the St value at BH3 was the lowest. The analysis of soil mechanical properties indicates that there was a positive correlation between soil bulk density,clay particle content and Cu(r=0.657 and 0.782,p<0.05),while there was a negative correlation between soil porosity and Cu(r= - 0.529 and - 0.414,p<0.05). In addition,there was a significant negative correlation between soil sensitivity(St)and fractal dimension(FD),pore number(NOP)(r= - 0.611, p<0.05). In the regression analysis,it is further revealed that there was a negative correlation between Cu and soil porosity,and St and NOP followed a logarithmic decreasing relationship. In the principal component analysis,the first principal component(PC1)was mainly dominated by the pore number,fractal dimension and clay content. PC2 was mainly composed of Cu and bulk density,and PC3 was jointly driven by soil porosity and soil shear strength. These indicators jointly highlight the importance of soil pore structure and physical properties in the evaluation of shear strength.[Conclusion]This study provides a scientific basis for an in-depth understanding of soil characteristics in coastal reclamation areas and offers important references for research on the stability of engineering construction,slope stability,evaluation of soil erosion resistance,and analysis of plant growth conditions in coastal areas,which is helpful to promote sustainable development of agriculture in coastal areas.