Experimental Study On Supporting Mechanism Of Soil Nails And Working Performance Of Soil Nailing Wall In Beijing

This paper took soil nailing wall of deep foundation in silty clay and silty sand asresearch objects, supporting mechanism of soil nails and working performance of soilnailing wall were studied by the in dependent designed physical model test system.Firstly, the physical model, testing system and testing procedure were introduced;Secondly, the distribution and change law about earth pressure, axial force of soil nails,horizontal displacement of wall top under excavation and loading circumstances;Thirdly, FLAC3D simulated study was taken based on the physical model test. Finally,applied research of soil nailing technology was implemented combine with engineeringpractice. Through a series of research, there can be found:(1) Earth pressure of soilnailing wall showed first increasedthen decreased during the stage of excavation, andthen gradually increased, earth pressure of pit bottom was increased straightly.(2)The axial force of soil nails were influenced by the excavation of the nearest soil layerbelow mostly, the maximum of horizontal displacement and soil nails axial force wereappeared at the same position.(3)The excavation of the deep foundation is the mainlyreason for the horizontal displacementincrease of the wall top, the displacement of thewall increased with the excavation, and when a uniform load was loaded on the wall top,horizontal displacement of the wall top almost increased linearly with the increase ofthe loading.(4) When the soil is the silty sand, the maximum of the horizontaldisplacement of the wall should be controlled under4‰of the depth of the pit. Whenthe maximum is larger than4‰, some measures should be taken to keep the wall stable.