Study on Deep and Large Foundation Pit of a National First-Class Key Tomb Protection Project

Table 3

Complexity of soil layer.

Foundation complexity	Foundation soil properties, degree of weakness, and hydrological conditions
Complex	There is large super weak muddy clay within 2H depth; there is silt or sand with large thickness at the bottom of the pit, and the water curtain cannot be separated; there is a large area of thick fill and hidden pond distribution; hydrogeological conditions: it is adjacent to rivers and has hydraulic connection; there are aquifers with high permeability and microconfined water or confined water
Moderate	There is mucky cohesive soil or silt within 2H depth; hydrogeological conditions: there is a certain distance from the river, and there is no hydraulic connection
Simple	The soil property within 2H excavation depth is good; no dark pond distribution; hydrogeological conditions are simple