The Deformation Analysis of a Deep Frame Top-Down Excavation in Downtown Shanghai Based on the 3D FEM

Table 1

Protection grade of deep excavations.

Environmental conditions	Distance of the structure or properties from the excavation (s)	Protection grade
Heritage buildings, factory buildings with precision instruments and machines, important buildings with shallow foundations or short pile foundations, metro lines, flood control walls, very important services such as water mains and gas mains	S ≤ He	I
	He < S ≤ 2 He	II
	2 He < S ≤ 4 He	III
Common buildings with shallow foundations or short pile foundations, important services such as water supply pipes, gas pipes, and sewage pipes	S ≤ He	II
	He < S ≤ 2 He	III

Note. He is the excavation depth.