Study On The Force Characteristics Of Gravity Retaining Wall Under The Action Of Expansive Soil Swelling Force

Gravity retaining wall is the most common type of supporting structure in slope protection engineering,and the research on its force characteristics has been quite in-depth.However,in the support of some expansive soil slopes,the force characteristics of gravity retaining walls appear to be particularly special,and the relevant codes do not give specific instructions on how to consider the pressure of expansive soil in the retaining wall.This paper analyzes the expansive earth pressure of a gravity retaining wall when the wall is rough and the filling surface is inclined,and combines numerical simulation methods to study the influence of expansion force on the retaining wall,and proposes suggestions for improving the design of the retaining wall.The work done in this article is as follows:(1)Summarized the formation mechanism of expansive force,the relationship between expansive force and the change of water content,and the distribution law of swelling force of the slope,focusing on the analysis and summary of the action mode of the lateral swelling force of the retaining wall,and concluded that the swelling force is acting on Within the depth of atmospheric influence,the force first increases and then decreases,and it also presents a non-linear change when it acts on the back of the wall.(2)Taking the gravity retaining wall with the back of the wall vertical and rough and the filling surface inclined as an example,the nonlinear variable swelling force is introduced into the earth pressure analysis,and the expansive soil is derived based on the Rankine earth pressure theory and the thin-layer element method Active earth pressure formula,combined with engineering examples,compared with the existing Coulomb earth pressure formula and actual measured earth pressure,it is found that the calculation result of the expansive earth pressure formula derived by the thin layer method is closer to the calculation result of Coulomb earth pressure,and the calculation of Rankine earth pressure theory The result is relatively small,and the point of action is also low.The three theoretical calculation results are also larger than the actual measured earth pressure value.(3)Bring the results of the expansion force simulated by FLAC3 D into the theoretical formula,and find that the theoretical value of the expansive soil pressure obtained is close to the simulated monitoring value,indicating that the numerical simulation and the theoretical calculation are mutually consistent to a certain extent;applied by comparison The stress and strain of the model before and after the expansion force,it is found that the expansion force generated by the humidification of the soil at the depth of the atmosphere behind the wall significantly increases the earth pressure and displacement of the retaining wall,and the maximum shear force is close to the limit of the design requirements.(4)Comprehensive earth pressure theoretical analysis and numerical simulation results,and put forward relevant suggestions for the design and improvement of retaining walls.