Experimental And Numerical Investigation Of Active Earth Pressure Against Sandy Soil With Limited Width Subjected To Stable Seepage And Vibration Loads

With the dramatically rapid urbanization in China,the large scale deep foundation pit engineering with increasing challenges in its design and construction due to the complexity,is often encountered.The major features of such foundation pit projects are:(i)the foundation pit is super deep;(ii)the size of pit is very large;(iii)the pit is usually very close to the surrounding infrastructures;and(iv)the design and construction of the foundation pit is rather complex.The deep foundation pit engineering is closely related to multi-disciplinary subjects,such as geotechnical engineering,structural engineering,as well as the geomechanics.In particular,over recent years,increasing attentions have been paid to investigate the stability of foundation pit under seepage and traffic loads.However,the studies on the active earth pressure against sandy soils with limited width subjected to seepage and traffic loads have been rather limited.In this thesis,in terms of the situ-conditions,both experimental and numerical studies arecarried out to investigate the active earth pressure exerted in the sandy soils under both seepage and traffic loading conditions.Then,some useful conclusions are achieved.The main research work completed in this thesis is briefly elaborated as follows:(1)An experimental model was designed and manufactured to investigate the earth pressures against soils under seepage and traffic loads.Then,theearth pressure meter and osmometer employed in current tests were calibratedin terms of the measured data for the oil pressureand the earth pressure.Finally,3 preliminary tests for the active earth pressure were carried out on the sandy soils under displacement mode.(2)Experimental investigations were performed on the standard sands with limited width under stable seepage loading condition.The evolution of the total earth pressure and the pore water pressure exerted in the soil with width of 65 cm and height of 100 cm were monitored during the whole movement process of the retaining wall.Then,comparison studies between the experimental and theoretical results were carried out.(3)Experimental investigations were performed on the standard sands with limited width under vibration conditions.The active earth pressures exerted in the soil with width of 65 cm,and height of 80 cm were measured for the three scenarios with “short distance”,“medium distance” and “far distance”,respectively,between vibrator and moving retaining wall.In the meanwhile,studies were conducted by comparing the experimental data with the theoretical results.(4)For the above two cases for the sands under stable seepage and vibration conditions,simulations were also performed by conducting finite element analysis via ABAQUS.Comparison studies between the experimental and numerical results were then conducted.