| Soil nailing supporting technology is applied widely in deep foundation pit support engineering, when the reinforcement is used as soil nailing, its advantage of high strength is not fully played. When the foundation pit and some geotechnical reinforcement which used as temporary works reach the end of their useful lives, millions of tons of reinforcement materials are buried permanently under the ground each year, and they cause a large waste of building materials resources, invade and affect the using of the underground space.More important, they will produce rust pollution and cause long-term effect on soil and groundwater environment. According to "Research and demonstration on composite material soil nailing support technology" of "Key technology of rock and soil reinforcement in underground excavation". This paper put forward that glass fiber polymer (GFP) soil nailing with light weight and high strength and removable wood plastic composite (WPC) panel could be used to instead of traditional reinforcement soil nailing and concrete surface layer. GFP rod mechanical properties were tested in door and WPC panel was designed about its disassembly property. Mechanical analysis and the derivation of the formula were done by anchoring features of soil nailing and the panel. At last, the feasibility of GFP soil nailing was verified by the FLAC 3D simulation. The main conclusions are drawn as following:(1) The properties of enhanced body and matrix in composite material were studied, and the soil nailing composite material in application-glass fiber polymer (GFP) was put forward, the features of soil nailing support technology were analyzed. Traditional soil nailing material-reinforcement was simply compared with glass fiber polymer, and the latter had superior properties such as anti-corrosion and high strength, and both of them had little difference on the price. The research proved reasonable that glass fiber polymer instead of the reinforcement, and it will have more broad development prospect.(2) The tensile properties of indoor test on GFP threaded rod with the diameter of 18 mm and 25 mm showed:initial strength of GFP threaded rod is carried by the matrix, and then late strength is carried entirely by glass fiber body. Carrying capacity increases and the strength decreases with the diameter increasing.For the coefficient k,0.75 is recommended in the formula of GFP rod tensile.(3) GFP rod in-plane shear strength was studied and tested, some conclusions were drawn:in-plane shear strength of GFP rod with the diameter of 18 mm and 25 mm are almost equal. In further, theoretical formula from the mixed laws can not be applied to GFP rod. The paper put forward that in-plane shear strength of GFP rod should include two parts:the matrix and fiber adhesion strength, shear strength of the matrix. Bending test was done to the above rods, and the change law of bending strength as follows:GFP rod is smaller in the diameter, bending carrying capacity is smaller. Bending strength is inversely proportional to the diameter size of the GFP rod, bending strength reduces more quickly with the diameter increasing. By properties analysis, the conclusion can be drawn that the failure cause of GFP rod is not tensile stress, but compressive stress. At the same time, the research on corrosion resistance shows that GFP rod has strong acid resistance, alkali resistance, salt resistance and freeze-thaw resistance.(4) Mortar's mix proportion (cement:sand:water) 1:1.5:0.4 is most suitable for grouting through the test, the carrying capacity of GFP rod with 18 mm in diameter improves with the mortar strength grade increasing; the diameter size affect on bond strength less obviously; when bond length reaches or exceeds critical bond length, average bond stress drops as the bond length increases.(5) The law of the deformation and mortar bond stress between the smooth rod and the threaded rod were compared. It indicated that the progress of the threaded rod carried the force:chemical adhesive plays a prior role ahead of the friction, then the friction plays a larger role, chemical adhesive disappeared,at last the mechanical bite force between GFP threaded rod and the mortar begins to carry the main load, and it is primary role.Three types of force should be considered to reflect effectively bond strength between GFP threaded rod and the mortar, so bond strength theory formulas should include the formula of each force. (6) Wood plastic composite material was put forward to instead of traditional network concrete surface layer. A new type of stitching wood plastic composite panel in soil nailing support for slope protection can be pieced together to form neat and sealable support interface and dismounted, recovered and reused after temporary support has completed.The anchorage of soil nailing and the panel was studied out.The indexes and formulas of GFP soil nailing and WPC panel in design and calculation were put forward.(7) FLAC 3D was used to simulated reinforcement soil nailing and GFP soil nailing construction. The calculation shows that GFP soil nailing carrying load are less and more evenly, and change law has a certain distinction comparing with reinforcement soil nailing. GFP soil nailing has much greater displacement that is within the specified range and meet the requirements. Both is basically the same in plastic zone. GFP soil nailing support is available; the displacement should be controlled in the construction of GFP soil nailing support.
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