What happens to the bearing capacity of soil when the groundwater table rises due to flooding?

When the groundwater table rises due to flooding, the bearing capacity of soil generally decreases. This is primarily because the presence of water in the soil voids reduces the effective stress, which is critical in determining the soil's strength.

In saturated conditions, the weight of the water adds to the pore water pressure, effectively reducing the soil's ability to support loads. When soil becomes fully saturated, its cohesion and frictional resistance are diminished, leading to a reduced overall bearing capacity. The moment the water rises, the effective stress acts on the soil skeleton decreases, leading to an increased likelihood of failure under loads that the soil could otherwise support when in a dry or less saturated condition.

Also, flooding can cause erosion and destabilization of soil particles, further impacting the bearing capacity negatively. Thus, the correct understanding of the impact of rising groundwater is that it leads to a decrease in the soil's bearing capacity, making the correct answer to the question clear.