How deep underground does this wall design go?
“How deep underground does this wall design go?”
Generally, the minimum foundation is about two feet thick and six feet deep of steel reinforced, high strength concrete. Local designs vary based on local conditions though, and the thirty foot bollards sometimes sit a bit deeper - meeting up with bedrock and up to six feet thick in places in San Diego.
There are several anti-tunneling technology programs that are deployed as well. Some can look quite deeply.