Loosening, crushing, excavation and transportation projects of soil and rock.

According to the geotechnical properties, earthwork excavation is divided into earthwork excavation and stone excavation.

According to whether the construction environment is open-air, underground or underwater, it can be divided into open excavation, hole excavation and underwater excavation.

In water conservancy projects, earthwork excavation is widely used in site leveling and slope cutting, and foundation excavation of hydraulic structures (sluice, dam, spillway, hydropower plant, pumping station building, etc.). ), underground cavern excavation (hydraulic tunnel, underground powerhouse, various flat tunnels, shafts and inclined shafts), river course, channel excavation and dredging, packing, building stone, concrete aggregate mining, cofferdam or temporary buildings such as masonry and concrete.

Mining method

Earthwork excavation is a key process in the initial stage of the project and even in the construction process.

Before construction, according to the scale and characteristics of the project, topography, geology, hydrology, meteorology and other natural conditions, construction diversion mode and project progress requirements, construction conditions and possible construction methods, the excavation method should be studied and selected.

Open excavation includes comprehensive excavation, local excavation, layered excavation and sectional excavation.

Comprehensive excavation is suitable for engineering projects with shallow excavation depth and small scope.

When the excavation scope is large, it is necessary to adopt subsection excavation.

If the excavation depth is large, layered excavation will be adopted. Rock excavation is often combined with deep-hole bench blasting (see deep-hole blasting) and stratified by steps.

Segmented excavation is suitable for large-length canals, spillways and other projects.

Tunnel excavation includes full-face excavation, division excavation, heading method and other excavation methods.

earth rock excavation

Construction method

Earthwork excavation construction, including loosening soil, crushing, digging and loading, transporting slag and other processes.

Rock excavation, in addition to the soft rock can be shoveled by scarifier, generally need to use blasting to loosen and break.

Manual and semi-mechanized excavation, using simple tools, such as shovel picks, pneumatic picks, pneumatic drills, etc. Combined with lifting or simple small transportation tools, it is suitable for small water conservancy projects.

Some irrigation and drainage ditches are directly constructed by ditching machines and can be formed at one time.

Earthwork excavation of large and medium-sized water conservancy projects is mostly done by machinery.

① Open excavation.

In addition to drilling and blasting with various rock drilling machines, the main uses are: excavation machinery, such as various single bucket excavators (see figure) or multi-bucket excavators; Scraper machinery, such as bulldozers, scrapers and loaders; Rail transport machinery, such as locomotive traction harvesters; Trackless transport machinery, such as dump trucks.

According to different situations, various cooperation methods are adopted to carry out various operations such as digging, loading, transporting and unloading.

According to the project scale and construction conditions, choose the appropriate construction machinery and corresponding construction methods reasonably, and pay special attention to the cooperation of machinery and equipment to avoid weak links.

Under certain conditions, earthwork can be excavated by hydraulic excavation; There is also a method of blasting excavation, that is, throwing blasting or sublating blasting technology, which not only breaks the earthwork, but also abandons it completely or partially outside the design boundary.

(2) Dig a pit.

Generally, drilling and blasting method is commonly used for excavation, and machinery is used for excavation and loading and unloading operations; Full-face tunnel boring machine can also be used to excavate tunnels; Shield construction can be used in soil or soft rock stratum (see tunnel excavation and underground powerhouse excavation).

③ Underwater excavation.

Land excavation machinery such as cable shovel and grab bucket can be used, but various dredgers are usually used for joint operation with water transportation equipment such as tugboats and barges (see dredging).

Compilation of construction scheme

Under the condition of meeting the design requirements, engineering quality, construction safety and construction period requirements, the construction scheme is optimized through technical and economic comparison.

When making a construction plan, the following points should generally be considered: ① The excavation method and construction method can meet the requirements of excavation progress, and connect with the construction diversion, concrete pouring and other processes to meet the requirements of flood control and flood fighting.

(2) According to the hydrology, seasons and construction conditions, the construction sequence should be arranged reasonably, with rapid construction and balanced production.

(3) According to the excavation scale, soil-rock characteristics, working conditions and construction methods, choose appropriate construction machinery and equipment, and the digging, loading, transporting and unloading equipment should be reasonably matched.

(4) According to local conditions, arrange transportation routes and general layout of construction, as well as wind, water and electricity systems.

(5) Do a good job in earthwork balance deployment, pay attention to the combination of excavation and mining, and abandon and fill to avoid repeated transshipment.

Waste residue and soil field should occupy farmland as little as possible and should be reclaimed as much as possible.

Abandoned slag should avoid encroaching on the river to prevent flood discharge or raising the tail water level of the power station from affecting the power generation efficiency.

⑥ Take good drainage measures for construction, so as to discharge rainwater, surface water, groundwater and construction waste water that hinder the construction operation and project quality off site, and create good construction conditions for the project.

⑦ Ensure the construction quality according to the requirements of design and construction technical specifications.

Problems that may be encountered in construction, such as quicksand, slope stability, tunnel collapse, etc. , technical analysis should be carried out and solutions should be proposed.

Attach importance to construction safety, and formulate technical measures for construction safety according to safety, fire prevention, environmental protection, industrial hygiene and other regulations.

With the increasing development of water conservancy construction scale, the earthwork excavation of some large-scale projects in the world often reaches tens of millions of cubic meters, even exceeding 1 100 million cubic meters, such as the earth-rock dam in Tabella, Pakistan (the dam filling amount reaches 65.438+0.2 billion cubic meters) and the Gezhouba water control project in China.

1 100m3; The earthwork excavation of Itaipu Hydropower Station in Brazil is 6065438+ 10,000 m3.

Therefore, the mechanization level of earthwork construction in some developed countries is developing towards large-scale and high-efficiency. The main features are as follows: ① Develop large-capacity, high-power and high-efficiency earthwork construction machinery, such as excavators above 10m3 and dump trucks above 100t; (2) The machines used in each process are matched with each other in terms of capacity and efficiency; ③ Hydraulic technology is widely used; ④ Electronic technology and new materials are adopted, and automatic control technology is widely used; ⑤ Pay attention to the development of multifunctional machinery and special machinery; ⑥ Pay attention to the repair and maintenance of construction machinery.

philology

Modern Rock Blasting Technology, by U. Langeforth and B. Kirstello, translated from Modern Rock Blasting Technology, 3rd Edition, Metallurgical Industry Press, Beijing, 1983.

(U.Langefors

and

B.Kihlstr╂m,The

modern

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Blasting,

Almkvist

Stockholm, Wicksell, 1963. )