Stimulation Test Research Of Bolt Supporting Of Foundation Pit Considering Construction Process

The paper researches on bolt supporting of foundation pit considering construction process, through large-scale indoor stimulation test. A homogeneous soil foundation pit is set up firstly in the stimulation test; then excavating the foundation pit and bolt supporting construction is done. Through analyzing and arranging the test data, the paper attained change rules of soil stress state and anchoring segment stress and foundation pit side displacement in considering construction process, such as excavating the pit, drilling, grouting, forcing beforehand stress etc.. (1) When the foundation pit is excavated and unloaded, the soil stress state near the foundation pit wall changes obviously. The variation tendency is all reduced on the whole. (2) The cut stress of soil bolt anchoring segment is asymmetry distributing and decreases progressively according to certain rule. (3)The force of bolt is smaller ,no other than after the foundation pit excavating continues next step, the force of bolt will increase. (4)The side displacement of foundation pit presents the variation tendency increased with going on of construction process, the curve takes on the form of parabola on the whole.On the basis of stimulation test, it probes soil bolt anchoring and deformation mechanism. The conclusion is: The soil body around the foundation pit, steel bar, grouting body and rider cap of bolt is a forced whole(it still may include hanging net and shotcrete),it must be answered integrality on using whole mechanics model. It not only considers the whole mechanics system, but also considers whole forced process. Namely when carrying through mechanics analysis, the excavating process of foundation pit and joined process of bolt must be considered. In this way, the deformation of anchoring body can be calculated more integrality and accurately after foundation bolt supporting.