|Construction services, repair and finishing, rollshutters, garagegates.|
3% discount off the competitors' price!Main | Services | Portfolio | About Company | Contact | Dealer Info |
Excavation works include soil refining. Soil refining consists of following process:
Spade-work and subsidiary works precede/ accompany above-listed processes. Spade-work is realized before excavation. Subsidiary works are realized before or during earthwork process.
Soil refine process is mechanized by diggers, earthmovers, hydrodemolition devices, drilling devices and explosive assembly.
Excavation works include grouting processes:
During excavation works conducting the following physicomechanical soil characteristics must be considered: volume weight, humidity, power of inner coalescence of particles, ability to be loosened.
Foundaton work includes:
Foundation work may take from 5% up to 15 % of all the construction process depending on the building specifications.
WALL IN TRENCH
Wall in trench fence structures erection (cast-in-place, precast, cast-in-place prefabricated waterproof assembly).
DRILLING AND PILE DRIVING
ADDITIONAL INFORMATION ON EXCAVATION
Method of the excavation depends on specific conditions and amount of earth-moving work. Manual method is the best for this work. Filling of such foundation pit needs considerably less building materials and its walls are natural formwork.
In case of basement planning the use of manual excavation is inexpedient. To measure the depth of a foundation pit one uses a scale stick with marks on it. During excavation one must check if the depth does not exceed required measure. The subsequent fill can weaken soil bearing resistance. If the depth of a foundation pit accidentally exceeds required measure a foundation must be laid at this level.
The bottom of a foundation must be flat and horizontal. In case of slope building the bottom can consist of horizontal and vertical sections inclined at angle of 45o. In this case vertical changes are not recommended because of the possibility of crack formation during laying.
Earth and foundation wall strengthening are conducted in loose ground with threat of a side wall collapse. One fulfils it with the help of horizontal planks of 40-60mm. thick installed as a formwork and vertical timber- supported. Formwork sides are additionally strengthened by horizontal distance bars between walls. It is better to construct a concrete retaining wall (if a landscape is inclined too much ).
Depending on soil condition one can use one of the methods of soil consolidation which is aimed to increase bearing capacity. Most often we need such method during erection of two-or more-story building. In construction practice there are many methods of artificial consolidation. During housing one uses cementation, silication and electric silication. Artificial consolidation can be appointed by a developer after careful plot investigation.
Cementation is fulfilled by a special injector (perforated pipes) for consolidation of sandy and seldom clay soil. 400 cement mix in the ratio of 0,8 : 1 (water: cement) under pressure is filling all soil interstices. After injector is lifted the hole is filled by the mix too.
Silication is used while consolidation of fine and powder running sand by single mixed or double mixed composition based on a liquid glass. In single mixed composition one uses sodium silicate- liquid glass and sodium aluminate. In double mixed composition one in the second stage instead sodium aluminate uses calcium chloride. Grouts are pumped by injectors under pressure of 3-6 atmospheres and ……..soil within a radius of 0,3-1 m.
Electric silication speeds up working process and improves quality owing to transmitting of electricity through injectors.
All abovementioned methods of soil consolidation include special equipment and can be conducted by organizations which acquired corresponding techniques.
Earthworks (Great Soviet Encyclopedia)
Earthworks are engineering works which include excavation (earth development), moving of soil (placing process sometimes includes leveling and consolidation of soil). Earthworks are one of the most important stages of industrial, hydroengineering, transport and housing construction. Earthworks are directed to erect engineering structures of soil (dams, railways and highways, canals and trenches etc.), to build the foundation of a building or a construction, to project a plot, to provide earth-moving works seeking minerals. Earthworks, concerned with open cast mining, relate to a stripping (see Daylighting). Earthwork structures are created by earth excavation or embankment erection. Excavation, directed to soil extraction, is called a borrow. An embankment, erected while dumping of excessive soil, is called a disposal.
There are three types of earthworks: open, underground and wet. Nowadays earthworks are mechanized and fulfilled by high-performance machines. Territory clearance, earthwork layout, surface water venting, drainage system installation, soil consolidation etc. are related to preparatory and auxiliary earthworks. Methods of Earthworks: mechanical, blasting and hydromechanical.
Mechanical method of earthworks (the most common) are fulfilled by earth-moving machines such as a loader, production trucks, the grader, the bulldozer, the backhoe, the drag line excavator etc. To move a soil from hollow to laying place one uses transport method. In that case earth development is fulfilled by earth-moving machine (mainly excavators). After, soil is loaded on track/trackless vehicle or the creeper.
Means of transport are not necessary while excavation of canals, railways, highways, trenches and foundation pits, when soil must be moved over a short distance (150-200m.). In that case excavation involves the drag line excavator. This method is very effective during open-cast mining. The scraper and the loader are used to move soil over distance of up to 3000m. and form an embankment. Fresno scraper with bucket capacity of 10-15 m3 and tractors are usually used to move soil over the distance of up to 100m. Developing the soil in layers, the scraper gives an opportunity to select premium soil. Moreover, the scrapper partly levels and consolidates a soil lightening further soil consolidation works. Heavy soil is recommended to be loosened before scraper using.
Shallow trench development, design works, cut-and-fill, leveling, filling with soil transportation over the distance of 100-150 m. are performed by means of bulldozers. Use of bulldozers group (2-3 bulldozers in a line) is especially effective. To excavate trenches one uses a single-bucket excavator as well as a multibucket excavator. Planning, road blading as well as shallow trenches digging may be performed by power graders. Layer-by-layer soil consolidation is necessary during earthwork structure erection, foundation pits and trenches filling. It is performed by means of road rollers (smooth, pin, vibrating etc.), under narrow circumstances- rammers, vibrating rammers, ramming plates.
Blasting method involves explosive power to move the soil in required direction (see Pin-point blast). In many cases (especially dealing with large volumes) blasting method produces great economical effect.
Hydromechanical method also called as hydromechanization involves giants which develop soil by water head or a suction dredger which suck in the soil with the water. Hydromechanical method combines 3 stages of earthworks (developing, transportation, laying), that increases efficiency of this method. One uses combined methods of earthworks. For instance, mechanical method can be combined with blasting or hydromechanical etc. The choice of earthworks method is determined by a project.
Literature: Building code and regulations, part 3, section Б, chapter 1- Earthwork, Moscow, 1964; Technology and organization of construction, edited by Galkin I.G., Moscow, 1969.
Phone: +7 (495) 642-8-444
© 2005 MilanStroy. All rights reserved.