The purpose of tunnel survey is to ascertain the engineering and hydrogeological conditions of the location of the tunnel, and the impact of tunnel construction and operation on environmental protection. Provide the necessary survey data for planning, design, and construction, and analyze and evaluate the existing geotechnical engineering problems and environmental problems to propose reasonable design plans and construction measures, so as to make the tunnel engineering economically reasonable and safe and reliable.
Several stages of tunnel survey
The division of the tunnel survey phase should be compatible with the highway design phase, and is generally divided into: feasibility study survey, preliminary survey, detailed survey.
1. Feasibility study survey
Highway feasibility studies are divided into pre-feasibility studies and engineering feasibility studies according to their working depth. The survey in the pre-feasibility study mainly focuses on collecting and studying the existing literature; in the engineering feasibility study, based on the analysis of the existing data, it is necessary to conduct on-site surveys of each possible scheme through surveys and Make necessary explorations at important sites such as bad geological sites, and roughly determine the geological situation.
2. Preliminary survey
The preliminary survey is based on the approved construction feasibility study report recommending the construction plan, and the survey is conducted in the initially selected route. Its task is to meet the preliminary design requirements for data. According to the engineering geological conditions, the route plan is preferred. Within the basic direction of the route, an initial survey is conducted on the section that may be used as the tunnel line position. The survey will focus on the unfavorable geological sites to determine whether the tunnel can pass or how to pass. Provide all engineering geological data needed to compile the preliminary design.
The preliminary survey work can be carried out in the order of collecting data, selecting tunnel locations for engineering geology, engineering geological mapping, exploration, testing, and data collation.
(1) Collecting information
The preliminary survey should also collect the existing data, including the feasibility study report, obtain the preliminary topographic layout map of the location of the tunnel, and documents about the nature and scale of the project.
(2) Tunnel location selected by engineering geology
The task of the preliminary survey is to choose the optimal tunnel location scheme that is economically reasonable and technically feasible. When the engineering geological conditions in the survey area are relatively complicated, such as poor regional geological stability conditions, and adverse geological phenomena, special attention should be paid to engineering geological route selection.
Firstly, the approximate route position of the tunnel line should be selected from the perspective of engineering geology, and then the engineering geological conditions along the line should be fully researched and mastered, and as far as possible, a more valuable solution should be proposed for comparison, and the tunnel should be selected in a section with better geological conditions. To avoid major program changes due to engineering geological problems during detailed surveys.
(3) Sorting of preliminary survey data
The original data of engineering geological survey, including survey, surveying, mapping, exploration, testing, etc., should be filled in according to relevant regulations, and reviewed and inspected. The submitted materials include drawings, texts, and other materials, which are required to be clear and correct, and to comply with the relevant regulations and the design method of design documents.
3. Detailed survey
The purpose of detailed survey is to provide complete engineering geological data for line layout and construction drawing design through detailed engineering geological survey in accordance with design information such as construction principles, design schemes, and technical indicators identified in approved preliminary design documents.
The task of detailed survey is to carry out supplementary proofreading on the basis of preliminary survey, to further identify the engineering geological conditions along the line, and the engineering geological characteristics of key projects and bad geological sections, and to obtain the necessary engineering geological data. The construction drawing design of the location provides detailed engineering geological information.
Detailed survey work can be carried out in the order of preparation work, engineering geological mapping along the line, exploration, testing, and data compilation. As the detailed survey work needs to further find out the engineering geological conditions on both sides of the tunnel centerline and the major engineering geological problems of the unfavorable geological section on the basis of the preliminary survey, the detailed survey work is more detailed and in-depth. The depth should meet the needs of the tunnel lining design.