Editing Trenchless technology (section)

==Trenchless & construction==
Trenchless construction includes such construction methods as [[tunnel]]ing, [[microtunneling]] (MTM), horizontal [[directional drilling]] (HDD) also known as [[directional boring]], [[pipe ramming]] (PR), [[pipe Jacking|pipe jacking]] (PJ), [[moling]], horizontal auger [[boring (earth)|boring]] (HAB) and other methods for the installation of pipelines and cables below the ground with minimal excavation. Large diameter [[tunnel]]s such as those constructed by a [[tunnel boring machine]] (TBM), and [[drilling and blasting]] techniques are larger versions of subsurface construction. The difference between trenchless and other subsurface construction techniques depends upon the size of the passage under construction.

The method requires considering soil characteristics and the loads applied to the surface. In cases where the soil is sandy, the water table is at shallow depth, or heavy loads like that of urban traffic are expected, the depth of excavation has to be such that the pressure of the load on the surface does not affect the bore, otherwise there is a danger of the surface caving in.{{citation needed|date=December 2018}}