Why does short-term heavy precipitation easily lead to ground collapse?

This is because the groundwater level will drop rapidly after the rainstorm. At this time, the air pressure in the underground cavity will be reduced, and the soil layer above will be pressed down by atmospheric pressure, which will still cause the soil layer to collapse downward.

Especially in summer and autumn when rain is concentrated, if there is long-term heavy rainfall, the flow and erosion of water in underground soil will be very obvious, and soil loss will be aggravated. At the same time, heavy rainfall will aggravate the erosion of subgrade main body and surface soil, lead to the increase and deformation of surface rainwater channel, and may lead to the decrease of soil density or even the emergence of cavities in a certain underground space, and the pavement will suddenly collapse under the action of surface rainwater accumulation, soil and other heavy objects.

In my opinion, short-term precipitation does cause ground collapse, but other factors can not be ignored. We should know more about the possibility of hidden dangers and get along with countermeasures on this basis. So what other factors will affect the ground collapse? Let's have a look.

1 geological disasters

Some special soils have high strength and low compressibility when they are not soaked in water. However, once it is soaked in water, such as in the rainy season in the south, the long-term water accumulation caused by poor drainage will soften the subgrade soil and lose its bearing capacity, and the soil structure will be destroyed soon, resulting in the whole or partial subsidence of the subgrade.

2. The underground pipeline leaks and collapses.

Old and disrepair is the main hidden danger of urban underground pipeline operation. Some underground pipes are leaking due to disrepair. After the pipeline was damaged, water continued to penetrate into the soil layer. With the increase of these tiny channels, water will take away loose substances when flowing. With the loss of soil particles and soil, the ground gradually sinks, and when the rigidity of the ground structure layer is not enough to support the ground load, it will collapse.

3, illegal buildings, foundation treatment is not done well, resulting in superficial and local collapse.

Some construction units will also leave hidden dangers because of wrong construction, such as backfilling with inferior soil, or the construction soil is not easy to tamp. The loose soil in the underground will be washed away gradually by running water, and under the joint action of ground load and soil self-weight, cavities will gradually form, leading to collapse.

4. Overexploitation of groundwater is also closely related to land subsidence.

Due to over-exploitation of groundwater, the groundwater level will drop seriously, and the gap will be difficult to recover in a short time, so that the weight of overlying strata can only act on the skeleton composed of water-bearing media. If the supporting force is insufficient, the ground will settle or collapse.

As can be seen from the above, the causes of urban pavement collapse are very complicated. Of course, it is difficult for us to fundamentally suppress some induced natural factors, but we can minimize the risk of collapse through human intervention, remedial and preventive measures. For example, it can improve the scientificity of road planning, enhance the standardization of road construction, increase the rationality of underground pipeline laying and management, and strictly manage and restrict the use of roads, thus improving the safety of roads.