Settlement Deformation
　　With China's rapid development, municipal roads are also booming. During the development of municipal roads, problems related to subgrade and pavement are increasingly exposed. Let's take a look at the problems and causes of subgrade and pavement, as well as related construction technologies.
　　Uneven Settlement
　　Uneven settlement is a common problem in the subgrade and pavement of roads and bridges. It can lead to serious issues, such as vehicle jumping during driving, which not only damages the pavement but also poses safety threats to passengers, creating significant hidden dangers.
　　There are various causes of uneven settlement, such as unreasonable design during bridgehead construction; substandard embankment compaction; and inadequate treatment of the approach foundation.
　　Setting Up Transition Settlement Sections
　　When designing bridges, if the bottom is soft soil, the concrete strength should be a key consideration, and different settlement lengths should be set to meet design requirements.
　　Reasonable Structural Design
　　When designing highway bridges, the length and strength grade of the approach slab in the settlement section should meet design requirements. During subgrade construction, on the basis of meeting construction requirements, grid-type geonets can also be used to reduce shear damage to the soil by the subgrade. In structural design, factors affecting subgrade and pavement deformation should be fully considered and prevented in advance.
　　Controlling Deformation of Settlement Sections
　　Deformation of settlement sections can damage the pavement and even affect driving safety, so the deformation of settlement sections should be strictly controlled. To ensure quality requirements are met, the settlement length should be strictly controlled. Computer simulation can be used to simulate pavement settlement changes after construction. If the result is smaller than the expected set value, the settlement section meets quality requirements and construction can continue.
　　Precautions
　　Setting Up Approach Slabs
　　Vehicles passing continuously over the pavement generate large loads, which can damage the subgrade and pavement. Reasonable arrangement of approach slabs can keep the subgrade and pavement on a normal plane, aligning the subgrade bottom with the top of the approach slab. The approach slab can place both on the same plane, making the subgrade and pavement safer.
　　Soft Soil Foundation Construction
　　For soft soil foundations, methods such as plastic drainage, blasting, and dynamic compaction are generally used. Soft soil foundations are prone to causing settlement in some locations, leading to subgrade deformation. Therefore, careful consideration should be given when selecting subgrade materials. Preloading can be carried out to improve bearing performance and reduce pavement settlement to a certain extent.
　　Proper Drainage Work
　　The drainage system is the quality assurance of subgrade and pavement engineering. Therefore, the number of drainage pipes and trenches should be reasonably set so that pavement settlement meets relevant standards. Based on the extent of asphalt use and the groundwater conditions in the area, the subgrade should be appropriately raised, and the drainage system should be reasonably set to reduce damage to the soil.