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th but low levels of power between the different role of soil prone to pile fracture. Therefore, the construction of soft soil on the earth excavation pipe has a great impact. Excavation of the deployment and technical measures, should be around to avoid excessive soil stress release, to avoid excessive construction load of soil, reasonable control of soil displacement and stress release, such principles. 3 Operating Points Excavators deployed 1) The basis of soft soil prestressed concrete pipe replacement rate is generally around 4%, before excavation practical understanding of the following circumstances under which the preparation of excavation construction plan, deploy, and technical measures clearly digging: a site geological conditions, b around adjacent building (structure) and the need to protect the pipeline case, c enclosure design, d pile length, pile spacing, pile foundation design exchange rate situation, e piling order, piling records and other foundation construction situation. 2) Excavation should be carried out subskin, skin thickness should be controlled in each of about 2m (soil nailing pit envelope layer under the soil nail wall thickness control), after the excavation of excavation under the skin epithelium. Pit excavation 8 leaving in graded steps, step width and the depth of excavation over the next steps should be 5 or more. Earth pit should be set to avoid the pond scum ramp so weak block, put the soil on both sides of the ramp slope coefficient of less than 1: should be considered in the sprayed concrete slope protection, soil particularly bad should be added @ 200 200 steel mesh. Should be avoided in the earth piles on both sides of the ramp slope, such as dense pile can not be avoided should be considered or gunite reinforced grouted, or switch to steel bridge as the earthwork ramp. 3) Edge against edge piling excavation, excavation and pile interval should be pleted in 15 days or more (more than 10 days drilling play). 4) Caps, ground beam position if the soil is still poor, the appropriate use of artificial excavation, avoid digging machine loading and vibration effects on the soil. 5) Cut pile arrangement should think ahead. Excavation before exposing the surface of the pile should be cut first。 excavation process, the process should be based on subexcavation cut off. 6) Digging machines, vehicles should be chosen to avoid using large equipment. Should try to choose a small digging machines, such as PC100 below. Vehicles to avoid the use of earth pit 10t cart. Technical measures digging 1) Excavation should be carried out layer by layer evenly, on both sides of the soil pile height shall not exceed 1m. 2) Collision against digging machine shaft. Mechanical excavation to the top of the pile 1m 30cm on both sides of the pile with the soil excavated. 3) Digging machines, moving vehicles, routes and both sides of the pile, as the case should be ta