Study On The Behaviour Of Retaining And Protecting Structure With Reinforced Cement Soil Pile-Anchors

Retaining and protecting structure with Reinforced cement soil piles and anchors as a newtechnology in foundation pit supporting in safety, economy and construction convenience issuperior to the traditional method, especially whose reinforced effect on soft clay makes adistinct advantage and wide application prospect in soft clay area. But, up to now, there hasbeen lack of the systematical design and analysis theory, resulting in the calculation modecopied form that of the traditional bracing system such as soil nails, bolting, so that thepresent design and analysis method which get adrift to the real force and deformation andcan’t reflect the features of the supporting system of its own has little significance of guidancefor engineering practice. So, the theoretical research on the supporting system seriously fallsbehind with the practice. Thus engineering field urgently need for design theory research ofthe technology. Based on the above situation, the paper carriers out the investigation andanalysis of internal force, deformation and stability of foundation pit, with it access to certainreference value for engineering practice.Based on the practical engineering, on the basis of FLAC3D numerical analysis software，the paper establishes the corresponding geometry calculation model, which is specified withthe corresponding physical and mechanical parameters of geological materials is assignedwith Modified Cam Clay model suitable for soft soil, simulates the entire process ofexcavation and supporting so as to analyze internal force, soil displacement and supportingmechanism of the retaining and protecting structure. At the same time, from the perspective ofdeformation control of foundation pit, the paper focuses on action and influence law ofparameters on the behaviour of the supporting structure, such as pile spacing, pile length, pilediameter, pile inclination, pile elastic modulus, pile distribution, so that design parameters thesupporting structure considering displacement control of soil can be obtained for constructionreference. Also, the paper, using strength reduction method introduced into Modified CamClay, analyzes stability of the foundation pit, and compares retaining and protecting structurewith reinforced cement soil piles and anchors with traditional soil nailing wall to understandcharacteristics of the supporting structure more clearly. Also, the paper verifies the above numerical simulation with the engineering measurement, and analysizes rationality anddifference of the numerical canculation.The analysis shows that pile-anchor has not only anti-tensile capability, which is theleading role of pile anchor bracing performance, but also anti-bending ability pile-soil, andretaining and protecting structure with reinforced cement soil pile-anchors effectivelyimproves ability of displacement control on soil and overall stability of foundation pits, due topeculiar anti-shear capacity and anti-bending ability of piles and synergy of anti-shearcapacity, anti-bending ability and anti-tensile capacity.Finally, all the work is summarized, and some facing difficulty and deficiency is discussed,in order to provide some reference and suggestions for future research work.