GGU-TRENCH: General notes

Four safety factors must be determined to verify the stability of a diaphragm wall:

1. Safety against groundwater ingress
   (DIN 4126 (old); 9.1.1 or DIN 4126:2013; 6.1)

2. Safety against slippage of single grains or grain groups
   (DIN 4126 (old); 9.1.2 or DIN 4126:2013; 6.2)

3. Safety against the slurry level falling below the minimum level required for stability
   (DIN 4126 (old); 9.1.2 or DIN 4126:2013; 6.3)

4. Safety against slip surfaces endangering the stability of the trench
   (DIN 4126 (old); 9.1.2 or DIN 4126:2013; 6.4)

The verifications for 1, 2 and 4 are performed by the program. A verification for 3 must be estimated pursuant to DIN 4126 (old), 9.1.3 or DIN 4126:2013; 6.3.

In comparison to the old safety factor concept, the new DIN 4126:2013 does not bring with it any substantial changes. The old standard requires the following verification for the stability of the trench (see Table 2 in old DIN 4126):

The new standard requires the following verification:

where _H = 1.0 and _E = 1.1 or 1.3 (see Table 4 in DIN 4126:2013).

Solved for _E we get

which corresponds to the relationship given in DIN 4126 (old).