Analysis And Control Strategy Of Differential Settlement Of Large-capacity Arch Culvert Joint Length In Widening Highway

As an important structural form of culverts,arch culverts are generally built on high embankments to withstand larger upper loads.Compared with ordinary small-size arch culverts,large-capacity arch culverts are subject to larger overfills.Outside the soil load,the requirements for its own stability are also stricter.Therefore,when connecting large-capacity arch culverts,in addition to considering the stability of the new and old arch culverts,the differential settlement of the new and old arch culverts must also be considered.In this paper,the finite element method will be used as the core to study the differential settlement characteristics of the large-capacity arch culvert length,the stability of the new and old arch culverts,and the differential settlement between the new and old high embankments.First of all,this paper conducted a field survey on the high-fill section of the Lianzhu Expressway’s low-to-high project,obtained the typical working conditions and related technologies of the new and old high embankments and old and new arch culverts in the project,and initially established the geometry required for numerical simulation The model,and based on the relevant design documents and normative literature,summarized the differential settlement control standards for the new and old large-capacity arch culverts depending on the actual project:the subgrade settlement of the transition zone expansion area within 15 years of opening to traffic is less than 5cm,and the transition zone expansion area subgrade total Settlement<15cm.New and old arch culverts and new and old high embankments are allowed to have a maximum settlement difference of 10cm.Then,the soil samples retrieved during the field investigation were subjected to relevant indoor tests to verify that the filling scheme adopted by the project meets the minimum design strength requirements.Subsequently,the mechanical properties of the roadbed fillers of different structural layers in each road section were studied to determine the various The stiffness strength attenuation law of roadbed fillers in different structural layers of the road section,combined with the analysis of the humidity field of the roadbed fillers,the long-term mechanical property parameters of the roadbed fillers were obtained.Among them,the analysis of the subgrade filling moisture field shows that the main reason for the change of the water content of each structural layer of the subgrade is the rise of the groundwater level,followed by the impact of atmospheric rainfall and evaporative seepage.Next,the ABAQUS software is used to establish a three-dimensional numerical mechanical model in combination with the geometric model of the roadbed and the structure initially established through field investigation,and then the long-term mechanical property parameters of each structural layer filler of the roadbed obtained by geotechnical testing and humidity field analysis are imported into In the model,the three-dimensional numerical mechanical model can be constructed and the whole process of 15 years of operation will be simulated.Through numerical simulation,it can be concluded that the relationship between the new and old roadbed and the structure of the old and new structures is the weight of the roadbed>moisture field change>driving load,and the length of the transition section is optimized to(3～5)+(1.25～2)h,where h is the height of the roadbed At the same time,the study on the differential settlement control of arch and culvert joint lengths with different geometric shapes shows that the larger the span of the arch ring or the higher the net height of the culvert platform,the greater the overall settlement of the old and new arch culverts.Finally,the orthogonal test is used to verify the correctness of the numerical simulation results,clarify the effect of the three factors of the transition section length,the arch ring span and the net height of the culvert on the stability and differential settlement of the new and old arch culverts.The primary and secondary relationship of factors in design and construction is:the net height of the culvert has the greatest impact on the differential settlement of the old and new arch culverts,the span of the arch ring is second,and the length of the transition section is ranked last.