| With the development of the modernization of our country,rail facilities and infrastructure construction to a great depth direction,the rapid construction of urban underground structure,the ensuing underground structure leakage problems more frequently,resulting in the deterioration of the environment in underground buildings,the durability of the structure is reduced,seriously affecting the structure beauty and use functions,its safety and applicability will also cause an adverse impact.In order to ensure the safety and normal use of underground buildings,it is necessary to carry out plugging treatment.In the treatment of seepage water leakage in underground structure,grouting is a common measure.At present,besides cement based materials,organic polymer materials are the focus of research in recent years.Single organic materials such as acrylic acid materials slurry viscosity is low,good irrigation,the generated curing material bond strength is high and has good stability,but the gel speed and gel effect is easy to be affected by water dilution;Absorbent resin plugging materials have short gel time,good expansion performance in water,and can quickly gel and plug the seepage channel in the presence of water,but the strength of the solidified material is low and the adhesion is not strong.In this thesis,acrylic salt and water absorbent resin grouting material as compound raw materials,acrylic salt-water absorbent resin composite material test research,in order to improve the respective shortcomings of single materials,in the compound to achieve the performance of single materials complementary,for underground structure seepage control to provide a good in gel speed,expansion plugging effect,mechanical properties and other aspects of the new grouting plugging material.In order to study the properties of acrylic salt-absorbent resin composite materials,this thesis,through laboratory tests,starts from the basic properties of materials and seepage prevention and plugging mechanism,and studies the basic properties,durability and microscopic morphology of materials.The main research contents and conclusions are as follows:(1)The basic characteristics and advantages and disadvantages of acrylic salt grouting materials,absorbent resin materials,grout composition,reaction mechanism and plugging mechanism are summarized and analyzed.The gel time,expansion rate in water,bonding strength and compressive strength of sand body of the acrylic salt-absorbent resin composite material were determined.The dry shrinkage performance test,dry and wet cycle test and aging test were carried out according to the durability of the material,and the microscopic morphology analysis and model test were carried out.(2)The gel time of acrylic salt-absorbent resin composite material is significantly shorter than that of simple acrylic salt material.The addition of absorbent resin can shorten the gel time of material up to 47%.With the increase of absorbent resin content,the gel time of slurry was gradually shortened,but when the absorbent resin content reached a certain value,the gel time shortening rate became smaller and tended to be stable.With the increase of the grout mix ratio,the gel time of the compound material basically increased first and then decreased.When the grout ratio is 5:1 or 8:1 and the absorbent resin content is 1.5%,the gel time can reach 10 s.And the material from the slurry to the curing process,in the exothermic state,which is favorable for underground engineering seepage control in some low temperature environment.(3)The composite material has the higher bond strength and good adhesion of acrylic salt and the water swelling and plugging ability of water absorbent resin,and obviously improves the water loss shrinkage degree of single composite material.The maximum bond strength of the composite material can reach 118 k Pa,and the bond strength of the composite material is significantly higher than that of the water-absorbent resin,but it is lower than that of the simple acrylate material,and the overall reduction range is less than 19%.With the increase of waterabsorbing resin content,the water-absorbing expansion rate of the cured material increased,and the shrinkage rate of water loss decreased significantly,and the dry shrinkage phenomenon was reduced.The dry shrinkage rate of the cured material of the composite material decreased by17.6%～32.1% compared with that of the simple acrylate curing material.The water leakage plugging effect of expansion plugging can be better played,and the composite material of acrylate-absorbent resin has better adaptability to the environment.(4)The compressive strength of the composite material is significantly improved compared with that of the water-absorbent resin material,but it is smaller than that of the simple acrylic salt material,and with the increase of the water-absorbent resin content,the compressive strength of the material also gradually decreases.The compressive strength of the acrylic saltabsorbent resin material is generally low,less than 1MPa,the larger the grout mix ratio A:B,that is,the more the acrylic salt A component,the compressive strength of the solid sand body continues to increase,and the increase degree slows down gradually;With the increase of the proportion of water,the compressive strength of the solidified sand body decreases.(5)The compressive strength of the acrylic salt-absorbent resin composite decreases obviously in the early stage of aging,and then the performance decreases slowly.With the increase of temperature,the compressive strength of the composite material solid sand body gradually decreases.The higher the temperature of the material,the higher the compressive strength and the faster the decline of energy.Under various aging conditions,the compressive strength of the solid sand body is kept above 0.2MPa as required by the standard,and the material has a certain stability in the state of hot oxygen.(6)Model tests were conducted to simulate the grouting plugging process under different crack widths,dynamic water velocity and grouting position conditions and to evaluate the grouting plugging effect.It is found that the composite material has a certain diffusion capacity in the reverse direction of water,and the material has a certain ability to overcome the blocking effect of water leakage.The farther the grouting position is from the water inlet,the longer the two-way diffusion distance and the larger the diffusion area of the slurry.In the actual project,according to the environmental situation,seepage cracks,by adjusting the grouting position,grouting pressure and material ratio and other influencing factors,in order to better play the role of acrylic salt-absorbent resin composite material,to achieve the purpose of underground engineering seepage water control. |
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