The effective桩 length in the construction of Larsen piles - broadly speaking, any pile driven to reach a certain elevation for the first floor of a building to meet usage requirements is considered effective, and thus, all pile lengths are effective lengths. For instance, this includes piles for buildings situated near water or the sea. The same applies to the retaining piles of buildings primarily subjected to lateral pressure.
In a narrow sense, piles refer to those that transfer the weight of upper structures to the foundation. If the foundation is as hard as rock and has sufficient bearing capacity, it is called an end-bearing pile. Conversely, if the foundation is not strong enough for end-bearing and relies on the frictional force of the surrounding strata, it is termed a friction pile. All friction piles have a length that is, of course, considered effective. However, end-bearing piles should ideally be as short as possible, meaning much of their length is considered ineffective. In reality, there is a spectrum between the two, with the effective pile length determined by the proportion of the pile that is in friction.