Reason for Road Subsidence

Soil Subgrade IssuesPoor bearing capacity of subsoil, high compressibility, or the presence of soft underlying layers can lead to excessive settlement of the subsoil under the action of road vehicle loads and natural factors, causing the road surface to sink. For example, wet and soft clay or silt-rich soil foundations are prone to such situations.

Groundwater Level FluctuationsWhen groundwater levels rise, the soil beneath the foundation becomes saturated, reducing its shear strength. Conversely, when groundwater levels fall, it may increase the effective stress in the soil, causing soil compression and deformation, leading to road subsidence.

Pavement structural layer damagePoor quality of subgrade or base material, and inadequate construction quality, such as insufficient compaction and improper material mix, can lead to the gradual deterioration of the structural layer under the repeated loads of vehicles, causing the road surface to sink.

Pipe LeakThe drainage and water supply pipelines beneath the road have leaked, causing water to erode the subsoil, altering its properties and creating voids or loose areas, leading to the sinking of the road surface.

Methods for Road Subsurface Reinforcement

Grouting reinforcement methodBy injecting cement slurry, cement mortar, or chemical grout into the soil beneath the foundation through drilling, the soil pores are filled, enhancing the soil's compactness and strength, thereby stabilizing the foundation and preventing further pavement settlement. Suitable for loosely compacted soil foundations with minimal settlement. Depending on different geological conditions and engineering requirements, options such as compaction grouting, crack grouting, or penetration grouting can be chosen.

No Chinese content provided. Please provide the text to be translated.Excavate the soft soil layers within a certain depth range of the subsidence area, then replace them with materials of higher strength and lower compressibility, such as sandstone, loam, and graded crushed stone, and compact them in layers. This method is suitable for situations where there are soft layers in the shallow foundation soil with significant subsidence. The selection of replacement materials should be determined based on the specific engineering geological conditions and design requirements.

Reinforcement methodIn the pavement structural layer, geogrids and geocells, etc., are laid as reinforcing materials to enhance the overall integrity and tensile strength of the pavement structure, distribute vehicle loads, and reduce pavement deformation and settlement. Reinforcement methods are usually combined with other strengthening techniques for improved results.

Root Strengthening MethodRoot piles are set around or beneath areas of road subsidence, with the piles connected to the road structure as a single unit to collectively bear the upper loads. Root piles enhance the load-bearing capacity and stability of the foundation, effectively controlling road subsidence. They are suitable for sections with poor subsoil conditions and high requirements for road deformation control.

Micro-pile Reinforcement MethodMicro-piles are small-diameter drilled piles that offer ease of construction and minimal environmental impact. By installing micro-piles in the subsurface areas of the road, the load from the road is transferred to the deep, stable soil layers, thereby achieving reinforcement.

Construction Key Points for Road Subsidence Reinforcement

Investigate the cause accuratelyPrior to construction, a thorough investigation of the reasons for road subsidence is necessary. This involves geological surveys, underground pipeline detection, and other methods to accurately determine the properties of the subsoil, changes in groundwater levels, and the distribution of underground pipelines, providing a basis for selecting appropriate reinforcement methods.

Reasonable design solutionsBased on the causes and extent of road subsidence, traffic flow, engineering geological conditions, and other factors, a reasonable reinforcement plan should be designed. The reinforcement plan should meet the usage requirements and safety performance of the road, while also considering the feasibility and cost-effectiveness of construction.

Rigorous construction quality controlDuring the construction process, it is essential to strictly adhere to the design requirements and relevant specifications. Control the quality of materials, construction techniques, and parameters such as grouting pressure, grouting volume, and the compaction of replacement materials. Strengthen monitoring of the construction process to promptly identify and address issues.

Traffic Organization and Safety AssuranceRoad subsidence reinforcement construction is often carried out on busy roads, requiring reasonable traffic organization and effective safety measures to ensure the safety of vehicles and pedestrians during the construction period. Warning signs and traffic guidance facilities can be set up, and a dedicated traffic controller should be arranged.