I would like to ask the tunnel step method excavation, the height of each step is how to divide?
On the circular arc heading cutting method, the excavation of each cyclicfootage and steel frame with same interval, after the excavation will be used in the initial support, the excavation behind the steps of 8~10m, after the excavation construction of initial support and invert, and then the middle rock pillar grouting reinforcement. (4) of excavation the surrounding rock and the surrounding rock in deep buried section IV and supporting: IV rock by step excavation method, step up the steps behind 8~10m, up and down the steps of primary support construction must follow with the excavation. Rock class take the whole section excavation method. (5) are the simple types of rock excavation self assembling drilling trolley, with dump truck shipment mucking loader. In order to ensure the safety and stability of tunnel construction in soft rock section, the construction must follow the "weak blasting, little disturbance, short excavation, strong support and frequent measurement, tight lining", in the application of The following measures shall be taken
The side ditch construction using composite steel formwork. (1) the temporary facilities of tunnel construction plan layout: in the single ended due to tunnel entrance, temporary facilities of tunnel construction in tunnel exit to the right. The layout for the layout of wind mechanical equipment in the right side of the roadbed export based on the terrain conditions, reservoir located in the left side from the position of about 80m. In the mechanical approach immediately after the entrance of earth excavation construction, roof slope and drainage ditches slope anchor slope reinforcement, well hole digging for. (2): the excavation and reinforcement the mechanical construction, according to the construction method of Subgrade Earthwork excavation, dig to the rock when, in order to minimize the disturbance of the entrance slope and subgrade slope, must adopt the method of weak blasting and presplitting blasting for excavation. The entrance slope using hang net shotcrete reinforcement, to facilitate the safety hole (3). The excavation and support of the shallow section of the surrounding rock of the cave: the construction method adopts the step method, and the advanced grouting bolt is adopted on the stage
Tunnel excavation adopts mechanical construction, tunnel excavation using simple self assembling drilling trolley, millisecond detonator, in order to improve the effect of smooth blasting around the eyes, around the eye using special Nonel detonation. Tunnel outlet using muck loader, dump truck with transport ballast. Two tunnel lining concrete use of the length of integral pouring formwork trolley 12M, concrete mixing station in centralized mixing, concrete transport vehicle transport pump into the mold.
