Study On Mechanical Behavior Of Prefabricated Corrugated Steel Lining Structures In Cross Passage For People And Vehicles

With the continuous progress of tunnel construction technology and technology and the needs of tunnel operation and management,it is urgent to have a new tunnel lining structure and the corresponding construction technology to improve the quality of tunnel engineering,speed up the construction speed,reduce the cost of tunnel construction and improve the construction environment.Because of its good mechanical properties and high efficiency of construction,fabricated corrugated steel plate has been applied in highway Bridges and culverts,underground integrated pipe corridors and open-cut tunnels in recent years.As the communication channel between the main tunnels,because its section is relatively small,the prefabricated structure lining can improve the construction environment,improve the construction efficiency,and realize the assembly and standardization of construction technology.Therefore,it is of great significance to carry out the research on the prefabricated structure lining.Based on this background,this thesis intends to study the mechanical behavior of prefabricated corrugated steel lining structure as the lining structure of tunnel cross passage for people and vehicles.The mechanical properties of the assembled corrugated steel lining structure under single specific load,different vertical loads,different sizes of fabricated corrugated steel plates,different tunnel depths and different levels of surrounding rock were studied,and the mechanical behavior of the assembled corrugated steel lining structure was predicted by machine learning method.The main research contents and achievements of this thesis are as follows:(1)By analyzing the characteristics of corrugated steel plate and the interaction theory between corrugated steel pipe culvert(bridge culvert)structure and soil,the action mechanism of corrugated steel plate,as a flexible structure,is explained that corrugated steel structure and the deformation of the surrounding soil mutual influence and mutual contact: Under the action of earth pressure,the section of corrugated steel structure deforms,thus squeezing the surrounding soil mass.At the same time,the soil mass produces elastic resistance,restricting the deformation of corrugated steel structure.Then,the earth pressure distribution of the whole surrounding soil mass is uniform,reducing the bending moment of the whole structure,improving the bearing capacity and buckling stability.(2)The stress characteristics of prefabricated corrugated steel lining structures under a specific vertical load of 100 KPa were studied by numerical simulation,and the circumferential stress,axial stress and Mises equivalent stress of the whole structure were analyzed respectively,as well as the stress variation of the structure at the position of wave crest,wave and trough.At the same time,the deformation characteristics of prefabricated corrugated steel lining structure are analyzed,including the change law of vertical displacement and horizontal displacement,and the change law of displacement at the position of wave crest,wave neutral wave trough.(3)According to the influence of different vertical loads on the mechanical characteristics of the whole assembled corrugated steel lining structure,the change law of the circumferential tensile stress and circumferential compressive stress,as well as the change law of the vertical and horizontal displacement of the whole structure were analyzed under different vertical loads.(4)The mechanical characteristics of assembled corrugated steel lining structures with four different waveforms were studied,and the influences of wave spacing,wave height and wave thickness on the stress and deformation of the whole structure were analyzed respectively.The results showed that: In the vehicular cross passage of the tunnel,the waveforms of 380 mm×140 mm and 200 mm×55 mm have better deformation performance under vertical load.In the pedestrian cross passage of the tunnel,the prefabricated corrugated steel lining structures with four waveforms have better stress and deformation performance.It is found that when the thickness of prefabricated corrugated steel lining structure is less than 10 mm,increasing the thickness of corrugated steel plate can effectively control the internal force and deformation of the whole structure.In the actual project,the appropriate thickness of corrugated steel plate should be selected according to the actual situation.(5)The mechanical characteristics of prefabricated corrugated steel lining structure under different surrounding rock conditions are studied.The results show that the prefabricated corrugated steel lining structure of tunnel vehicular cross passage has good applicability within 30 m buried depth under the condition of class Ⅲ surrounding rock.Under the conditions of Ⅳ and Ⅴ level surrounding rock,the assembled corrugated steel lining structure of the tunnel vehicular cross passage is within 25 m and 20 m depth respectively.The assembled corrugated steel plate alone as the tunnel vehicular cross passage lining structure has better applicability.The buried depth is more than 25 m and20m respectively,so it is necessary to strengthen the unfavorable position of the arch foot.To ensure the safety of the entire structure.The prefabricated corrugated steel lining structure of pedestrian crossing tunnel has good applicability under the surrounding rock conditions of Grade Ⅲ,Ⅳ and Ⅴ and the tunnel buried depth of less than 30 m.(6)Machine learning method is used to predict the effectiveness of numerical simulation parameters of mechanical behavior of prefabricated corrugated steel lining structure.The results show that the prediction model error of maximum vertical displacement Dmax is the smallest,and the accuracy of prediction model is the highest.In pedestrian passage,the prediction model error of maximum vertical displacement Dmax and maximum circumferential stress Smax is very small,and the prediction model accuracy is very high.In general,the prediction result of pedestrian passage is better than that of vehicular passage.