Experimental Study On Mechanical Properties Of Non-foaming Polymer Grouting Materials

As an important means of maintenance and reinforcement,polymer grouting technology is widely used in the field of highway,tunnel,bridge,dike,dam and other traffic and water conservancy projects due to its advantages of fast construction speed,little damage to the structure and high economic benefit.The wind turbine tower foundation is the main bearing structure of the wind turbine,which bears all kinds of loads transmitted from the tower,blade and engine room of the upper part of the wind turbine.Its bearing capacity and stability are the basic guarantee for the safe and stable operation of the wind turbine structure.In recent years,it has been found that some fan foundations have defects such as honeycombs,hollows and cracks,which are major hidden dangers of long-term reliable operation of the fan structure.Polymer grouting technology is to inject slurry into the cracks of fan foundation through a grouting pump,which plays a role of reinforcement and repairing,thereby ensuring the stability of fan foundation.Non-foaming polymer grouting material is a new type of chemical grouting material for the reinforcement of wind turbine foundations.The strength and weakness of its mechanical properties play a key role in the maintenance and reinforcement of wind turbine foundations.Therefore,it is imperative to carry out systematic experimental research on the mechanical properties of this new type of polymer grouting material,which is the fundamental and key to the application of polymer grouting technology to the foundation maintenance and reinforcement of wind turbines.In this paper,a series of experiments on the physical and mechanical properties of polymer grouting materials are carried out.The main research contents and achievements are as follows:(1)By testing the basic physical properties of the non-foaming polymer grouting material,the apparent density,gel time and reaction temperature were measured,and the preparation process and curing reaction mechanism of the non-foaming polymer grouting materials were analyzed.The microstructure characteristics of the material were observed by SEM scanning electron microscope.(2)Based on the uniaxial compression test of the non-foaming polymer grouting material,its failure patterns and stress-strain curves under different sizes and compression rates were obtained.The changes of the compressive strength andcompressive modulus of elasticity of the non-foaming polymer grouting material with the specimen size and test loading rate were summarized,and the microscopic deformation mechanism of the material under the compression load was analyzed.(3)The uniaxial tensile test of the non-foaming polymer grouting material was carried out,the failure morphology and stress-strain curves of the polymer grouting material under different tensile rates were analyzed,and the changes of tensile strength,tensile modulus and elongation at break with the tensile strain rate were calculated,and the microscopic deformation mechanism of the material under tensile load was studied.(4)The torsional shear test of the non-foaming polymer grouting material was carried out,the failure patterns under different torsional rates were observed and the shear stress-strain curve was drawn.The changes of shear strength,shear modulus of elasticity and shear strain with shear rate were analyzed,and the micro deformation mechanism of the material under shear load was discussed.