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Design Guidelines Item: The term, "owner" refers to the property owner or their designated representative.
9.1 Wall embedment depth should be determined by the wall design engineer based on typical industry standard and specific site requirements.
9.2 If a global stability analysis is not included in the wall designer's scope of work, establish that when a global stability analysis is required by the wall designer, using their best engineering judgment, then the owner will contract with a geotechnical engineer for overall site stability. Global stability analysis should be run for a variety of conditions including:
|Sieve Size||Percent Passing|
|1 in (25 mm)||100-75|
|No. 4 (4.75 mm)||100-20|
|No. 40 (0.425 mm)||0-60|
|No. 200 (0.075 mm)||0-35|
We have identified a Design Envelope for the wall designer that defines the extents of an ICS evaluation within that envelope. An ICS analysis does not take into account a slope below the wall, as the bottom slip arc is located at the base of the bottom block. Therefore it will not provide guidance for what happens below the wall. One easy to identify guide for additional global evaluation may be found by reviewing where the ICS slip arcs with the minimum factors of safety originate. When a concentration of ICS slip arcs originate at the back of the Design Envelope, a complete global stability analysis should be conducted, See Figure 9-2.
9.3 For walls with global stability concerns, it is common to increase the stability by: