The general situation of Ali tunnel and Yangzhong drainage tunnel: the lithology of the crossing stratum is mudstone and limestone (below the arch) of Longtan Formation (P [2] LT) of Permian system, and the Quaternary artificial fill (above the arch)
. 
Overview of Yangzhong drainage tunnel: it undergoes high fill section of Huaguan road
. 
In order to implement the spirit of the provincial department’s teleconference on safety production of housing and municipal engineering held on January 22, Guiyang construction survey and Design Co., Ltd
. 
Luo Yuanqing, deputy chief engineer of the company, led our tunnel professional and technical personnel to carry out the design return visit and on-site safety hazard investigation
.
The drilling and blasting method is adopted for three heading excavation, the middle heading first and then the left and right main tunnels
.
Luo and the company’s tunnel professional and technical personnel mainly carried out design return visit and safety hazard investigation for the high-risk tunnel projects under construction of the company, namely, alishi tunnel on Longshui road and Yangzhong drainage tunnel
.
The diameter of single pipe jacking is nearly 5m, which is the largest pipe jacking project in our province at present, and it is a new major project in 2020..
.
Through the design return visit and on-site hidden danger investigation, it provides a good opportunity for learning and communication to improve the professional level of designers and the quality of drawings, and to find the deficiencies of design documents
.
Mr
.
Two way six lane
.
The structure is designed as double arch composite lining tunnel (as shown in the figure below)
.
At the same time, as a high-risk specialty, the tunnel specialty has strengthened the design concept of safety development, consolidated the defense line of safety production, eliminated the potential safety hazards, reduced the safety risks, and ensured the smooth and safe construction of the project during the Spring Festival by investigating the safety and quality hazards of the high-risk tunnel construction site
.
The maximum buried depth is 23m, the buried depth is about twice the diameter of the excavated tunnel, the buried depth is shallow and the geology is poor, so it is a high-risk tunnel
.
It is designed as double hole reinforced concrete pipe jacking, which adopts slurry and earth pressure balance double mode jacking machine to carry out jacking alone, and the launching well and receiving well are super large foundation pit
.
recently actively carried out design return visit and on-site safety hazard investigation
.
