Rotary Drilling Rig Project Overview

Project Overview

1, the project location: the project location on the equipment transfer costs, material procurement, season, weather, engineering unit price have an impact, so these factors need to be considered.

2、Type of project: There are many types of project foundation, such as high speed rail, highway, cement plant, power plant and so on. The type of project will have a great influence on the construction method and the progress of the project. Such as high-speed rail, highway piles scattered, accelerated geological changes, and strict supervision; while the cement factory, power plant piles dense, generally choose a higher and flatter site, and supervision is relatively loose.

3, geographic location: the project location as far as possible away from the mountainous areas, because the mountainous areas are more rocky, rapid geological changes; away from the river, because the geology near the river is mostly sandy pebbles, and groundwater is abundant.

4, season: winter construction not only additional construction costs, but also increase the construction difficulty, affect the construction quality.

5, the weather has a great impact on the construction, almost every builder has been stopped due to weather factors, including rain, snow on the project has the greatest impact, the investigation of the project must take into account this factor, such as winter rain in the south led to a long period of suspension of work.

Geology

The difficulty of the project is mainly caused by the following factors: geology, groundwater, pile diameter, pile length.

1, the type of geology: according to rotary excavation construction can be divided into geology

(1) Conventional geology: mud layer: soft plastic, medium plastic; soil layer: clay, loess, powder soil; sand layer: fine sand, medium sand, coarse sand.

(2) Moderately difficult geology: pebbles: mud pebbles, sand pebbles; pebble layer: breccia layer, gravel layer, conglomerate layer; sedimentary rocks: sandstone, mudstone, shale; weathered rocks: fully weathered, strongly weathered, moderately weathered.

(3) Highly difficult geology: weakly weathered; unweathered igneous rocks: granite, basalt.

2、Geological strength: no matter what type of geology, the difficulty of drilling is eventually measured by the strength of the geology

(1) Ultimate bearing capacity: For conventional geology to medium difficulty geology, the ultimate bearing capacity is generally used to measure the strength of geology.

Ultimate bearing capacity: pressure is applied to an area of 1 square meter until plastic deformation occurs. Such as 500 kPa converted gravity = 50 tons, 1 square meters on the application of pressure 50 gravity plastic deformation.

(2) Uniaxial compressive strength: the difficult geology ~ difficult geology are generally uniaxial compressive strength determination of geological strength.

Uniaxial compressive strength: the maximum pressure that a rock can withstand without side bundles, until the rock is pressurized to the stress required for rupture. Groundwater

Usually affect the rotary excavation construction of groundwater is mostly the upper layer of stagnant water (local waterproofing effect of the formation of aquifers) and submerged layer (the first stable waterproof layer on the groundwater).

1, water media: nature's rocks, soil are porous media, their shape, size of the pore, fissure or solution, some of which contain water, some do not contain water, some although water but difficult to permeability. Usually both permeable, but also full of water in the porous medium known as water-bearing medium.

2, the location of groundwater: for rotary excavation construction, the location of groundwater is of course the deeper the better. The shallower the groundwater, the more unfavorable to the rotary excavation construction, due to the mud pressure increases with the depth, so the shallower groundwater can only use the long barrel or mud wall process.

3, groundwater rich situation: for rotary excavation construction, the less groundwater the better. If the groundwater is rich, then the water-mediated geological layer must be stored, so it directly determines the mud quality (wall protection, pressure).

4、Geological report: the foundation pile must be analyzed by the design unit for geological and groundwater exploration, and provide geological report for construction reference. Through the text description on the geological report and the plan analysis, we can understand the geology and groundwater of the whole site.

5、Geological exploration (core): Exploration of foundation pile geology is divided into preliminary and detailed exploration. No matter which exploration method, core sampling is necessary. If the project is not started or just started, the exploration core is not destroyed, you can directly observe the core and analyze the geology. Pile diameter

The change of pile diameter directly affects the drilling ability

1、Torque: Increase in pile diameter means increase in the diameter of the drilling bucket, so increase in resistance arm = increase in torque load.

2、Pressurization：The pressurized cylinder outputs pressure to the drilling teeth on the drilling bucket. The increase of pile diameter means the diameter of the drilling bucket increases, and the number of drilling teeth increases at the same time. Pressure/area=pressure, so the increase of the pile diameter=pressure on each tooth decreases, which reduces the drilling capacity.

Examination of Party A

1、Four passes and one leveling: go to the construction site to inspect the road, water, electricity, communication and site leveling.

2、Acreage: whether the cost of occupied engineering acres is in place, you can go to the local households to understand the situation.

3, nuisance: observe the distance between the construction site and the residential area, to prevent noise nuisance due to nighttime shutdown.

4、Drawings: whether the engineering drawings have all been designed, Party A has got all of them.

5、Concrete: location of the mixing plant, whether it has been built, designed daily output of concrete cubic meters, cement storage capacity, the number of mixer trucks.

6、Reinforcement cage: location of cage production site, daily output quantity, transportation mode and transportation capacity.

7. Hole checking method: whether it is necessary to put down hole gauge, deep measuring tube, whether to use ultrasonic instrument to check the hole.

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