The groundstratum is quite complex, with silt layer and fine sand layer mixed, so the construction is difficult to be carried out and the requirement of pit support is strict.
基坑所处地层十分复杂，有较厚的淤泥层和细砂层，基坑支护要求高，施工难度大。
2
Theory of key stratum in ground control.
岩层控制的关键层理论。
3
On the other hand, gravel ground condition is a good bearing stratum for piles, which is often met with in civil construction.