Study On Anchoring Properties Of Non-Foaming Polymer Grouting Materials

With the development of geotechnical anchoring technology,new types of anchor rods,improved anchoring agents and other products are changing rapidly.Although the performance of anchoring materials has been greatly improved,they have not deviated from the essence of water participating in the reaction.For rock-soil anchoring,especially rock-soil masses that are sensitive to water,there is an urgent need for a new type of anchoring material that does not require water and can be quickly carried.In this paper,a new type of anchoring material,non-foaming polymer,is introduced to meet the urgent need of geotechnical anchorage technology for new,water-free and fast loading.Combining the technical characteristics of non-foaming polymer grouting,through the combination of indoor test,outdoor model test and numerical simulation,the mechanical properties of non-foaming polymer material,non-foaming polymer and screw steel and concrete The interaction mechanism between the substrates was studied to provide new support methods for rock and soil anchoring,especially for various emergency rescue projects,and to provide a reference for the application of non-foamed polymer anchors.The main work completed is as follows:(1)Through laboratory tests,uniaxial compression and tensile tests were carried out on the non-foamed polymer material to obtain the uniaxial compressive strength,elastic modulus,deformation under peak load of the non-foamed polymer material,and The tensile strength and elongation of the material,the non-foamed polymer material is a flexible material,and its strength index fully meets the requirements of the grouting material.(2)Through model tests,the average bonding strength between the non-foamed polymer anchor and the steel bar,as well as the influence of the steel bar diameter and anchoring length on the bond strength,were found.The bonding strength between the non-foamed polymer and the steel bar interface was found to be anchored The length and the diameter of the steel bar have a greater influence.The bond strength between the non-foamed polymer and the steel bar interface is 4.5MPa ～ 6.8MPa,which meetsthe requirements of engineering applications.(3)The central pullout test was used to study the bonding characteristics of non-foamed polymer and different strength concrete matrix.The distribution of axial force along the anchoring depth under different loads was obtained.The influence of the bonding force,when the matrix strength is not greater than 30 MPa,the bonding strength between the non-foamed polymer and the concrete matrix can reach0.98 MPa.(4)Using ABAQUS finite element software,the ultimate drawing force and axial force distribution of non-foamed polymer anchor rods under different anchor lengths and anchor thicknesses are simulated,and the calculation formula of the ultimate pull force under different anchor lengths is given;By comparing with the model test results,the rationality of the numerical model is verified.(5)Based on the model test and numerical simulation,a large-scale non-foamed polymer prestressed anchor model test was carried out,and the distribution of prestress in time and space was analyzed.The prestress loss is mainly concentrated in the first 24 hours after tension and locking,and is basically stable after 48 hours.The greater the axial force on the rod body,the greater the corresponding prestress loss.