Study On The Repair Material And Performance Of Drainage Pipeline Lining Based On UV-LED Curing

As an important part of urban infrastructure,municipal drainage pipe network is the material basis for the survival and development of the city.It is an important condition for ensuring the normal and efficient operation of the city and ensuring the healthy and sustainable development of the urban economy and society.It can be called the underground’lifeline’of the city.The scale of municipal drainage network in China is huge.The quality of the pipelines built in the early stage is not up to standard and the pipelines are in disrepair for a long time,which leads to the further expansion of urban black and odorous water bodies,low treatment efficiency of sewage plants,frequent accidents such as urban waterlogging and road collapse,and huge hidden dangers of safe service,which has caused serious loss of life and property.In this context,aiming at the problem that the repair materials in the field of drainage network repair are not environmentally friendly and the repair design theory is missing,this thesis carried out research on pipeline repair materials and bearing performance based on UV-LED curing.The main research results are as follows:（1）Functional design of UV-LED light curing lining and development of supporting equipment.The advantages of UV-LED lamps over traditional UV mercury lamps are analyzed.From the perspective of UV-LED light-cured resin,glass fiber cloth and other light-cured lining raw materials,the experimental study on the ratio of initiator and thickener,the influence of the wettability of glass fiber cloth and the structure of felt cloth on the mechanical properties of the material,and the experimental study on the ductility of the inner membrane were carried out,and the UV-LED curing repair hose material was formed.From the perspective of equipment improvement,the production process of lining hose with asynchronous folding and asynchronous glue filling proposed,and the corresponding equipment was developed.The results show that the resin system has good curing and thickening thixotropy when the addition ratio of initiator and thickener is 0.3%and 4.3%respectively.The A-860 glass fiber cloth is selected to make the liner hose have good wettability and mechanical properties after curing.The hose made by asynchronous folding process has more uniform inner film ductility,which reduces the risk of inner film damage.At the same time,the thickness of the liner pipe is more uniform and the ring stiffness is higher.Through the development of hose production equipment,products far higher than the requirements of domestic standards have been produced.（2）Study on the long-term performance of UV-LED light-cured repair materials.Through chemical corrosion resistance test and structural wear resistance test,the difference between the new material and the conventional CIPP material was com Pared and analyzed.A long-term creep elastic modulus prediction method based on linear extrapolation and nonlinear extrapolation was established by 10000h long-term mechanical properties test.The results show that the residual bending strength of UV-LED light-cured liner tube after immersion in long-term acid-base environment is much larger than the 80%requirement specified in the standard.After 10000 cycles of wear test,the average wall thickness loss of the liner is only 0.09 mm,which is much smaller than 0.3 mm of the German brand products.On the basis of 10000 h long-term creep test,through extrapolation analysis,it is found that the 50-year long-term bending modulus of UV-LED liner is 74%of the short-term modulus,which is much higher than the 50%value requirement in the existing standard.（3）Study on the external pressure stability of UV-LED liner under the influence of annular gap.By analyzing the existing theoretical models of annular gap buckling,the applicable conditions and differences of various models are clarified.The instability evolution mechanism of the UV-LED curing lining structure under the annular gap defect was discussed through the external pressure buckling test.The critical buckling pressure calculation model suitable for the UV-LED curing lining was proposed,and the annular gap defect treatment technology based on the grouting reinforcement method was formed.The results show that under the action of external water pressure,the buckling of the liner with annular gap defects has experienced several stages of initial micro-deformation,ovalization of the liner pipe,buckling along the short axis of the ellipse and buckling along the axial direction.When the annular gap is generated,the ratio of P_cr/P_cr-freeis less than 7,which means that the liner designed according to ASTM F1216 and CJJ/T 210 standards no longer meets the design stability requirements.Gap grouting can effectively improve the stability of the lining.When the ungrouting gap angle is small enough,its influence on the critical buckling pressure can be ignored.（4）Study on the external pressure stability of UV-LED liner under the coupling effect of uneven thickness and ovality defects.Based on the geometric expression of the radius of the defect lining structure,the characterization methods of non-uniform thickness and ellipticity defects are derived respectively,and the theoretical model of the coupling of non-uniform thickness and elliptic defects is established by using the principle of minimum potential energy.A two-dimensional liner structure model of UV-LED curing liner repair was established by finite element numerical analysis technology,and the influence of uneven thickness and elliptical defects on the external pressure stability of UV-LED curing liner was analyzed.The results show that by com Paring the data obtained by the finite element model simulation with the results calculated by the analytical formula,it is found that the maximum error of the critical load does not exceed 3.65%,and the error of the radial displacement value of point A corresponding to the critical load does not exceed 4.85%.Therefore,the rationality of the analytical formula is verified.（5）Study on the buried mechanical response of existing pipelines reinforced by UV-LED light curing repair materials.Through the self-developed soil box test system,the actual stress of the buried flexible pipeline before and after the repair with UV-LED solidified lining is simulated,and the stress and deformation characteristics of the pipeline structure under the action of soil pressure and the change of surrounding soil pressure are studied.Then,the finite element model of UV-LED lining pipe repairing flexible bellows was established by Abaqus finite element software,and the overall bearing capacity of the repaired pipeline structure and the strain variation of the lining material were further studied under the influence of different elastic modulus and different thickness.The results show that the ring stiffness of the pipeline structure after UV-LED lining reinforcement is significantly improved,and the overall load that the repaired pipe-lining structure can withstand is increased from 150 k N to 250 k N.The vertical deformation of the repaired pipeline decreases with the increase of the elastic modulus of the lining,and the displacement of the top loading plate also decreases.With the increase of lining wall thickness,the stiffness of the repaired pipeline is obviously improved,and the deformation is reduced.