CONSTRUCTION EXCAVATIONS
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INTRODUCTION
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WIDE SPATIAL EXCAVATION
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DRAINAGE OF THE EXCAVATION
1. INTRODUCTION.
Excavation - an earth structure in the form of a properly shaped space resulting from the removal of soil from it.
All excavations should be carried out with appropriate security measures. Do not excavate without slopes or spread to a depth greater than 1 meter in sandy soils and 1.5 meters in clay soils.
Excavations can be performed by two methods:
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frontal method - this method is effective for excavations with large depths, but small widths
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layered (longitudinal) method - this method is effective at large excavation widths. In addition to excavators, bulldozers and scrapers can be used to remove subsequent layers of soil. In another version of this method, the excavator excavates the width and depth of the bucket reach, which is then widened by a bulldozer-scraper
2. BERLIN WALL.
Application:
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temporary housing for deep excavations;
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load transfer in the form of soil pressure;
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with proper corrosion protection of piles and the use of a concrete or steel joint, it can be made as a durable retaining structure.
Building:
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construction made of piles, usually steel I-sections, spacing up to 3 m;
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filling in the form of a bar, usually made of wooden logs, as well as reinforced concrete or steel moldings;
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in the event of the appearance of a small amount of groundwater, a non-woven fabric is placed under the clip;
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casing support can be provided by ground anchors or a steel expanding structure consisting of strut caps and struts.
Production technology:
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after driving in piles, the clip is placed behind the shelves of piles successively as the excavation is deepened, which is carried out in stages of thickness adapted to the type and condition of the ground;
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in the case of a high level of groundwater, dehydration gradually starts during digging;
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the excavation is made to the ordinate of foundation of footings, benches, and in the case of non-bearing soils under the above, the excavation is deepened to the elevation of the bottom of these soils, they are removed and backfill with non-cohesive soils;
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all works can be carried out in a pipeline system, which allows construction works to be started before the final completion of the safety works and digging the excavation;
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the Berlin housing causes relaxation of the ground behind the housing and is therefore not recommended for making in the immediate vicinity of existing foundations or underground utilities;
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Berlin housing in contact with the newly designed structure, used on small plots, is the lost external formwork of the underground wall, on which vertical insulation is laid;
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continuous cap is used when it is impossible to design a spread or anchoring over the ceiling, after pouring which can be removed support, this solution prevents the execution of the outer wall, while anchor heads spaced every 2-3 m can be concreted in the structure, or windows allowing them to be cut off after completing the underground.
PHASES OF THE Erection of "FOUNDATION WALLS AT THE PROTECTION OF THE EXCAVATION" WITH THE BERLINSKA WALL.
FAZA 1
FAZA 2
FAZA 3
FAZA 4
FAZA 5
3. MICROPALES.
Application:
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walls protecting excavations in the vicinity of neighboring buildings.
Building:
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the palisade consists of micropiles with a diameter of 15 ÷ 35 cm,
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30 to 60 cm is usually sufficient between the erected and existing one.
Production technology:
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piles drilled at intervals not exceeding 3 diameters,
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when digging the trench, there is no need to place a joint between the microfiles, natural vaults are formed between the microfiles, which allow the palisade to be treated as a continuous wall fully protecting against loosening of the soil behind the housing, this is important when digging the excavation near the foundations of existing facilities,
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in the case of excavations with greater depths, the palisade is expanded, or anchors, making reinforced concrete or steel caps.
4. SEALED WALL.
Application:
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securing the excavation (prevent movement of the soil behind the wall in a horizontal direction),
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prevent the flow of open, ground or surface water behind the wall,
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ensure the takeover of the expected land and water pressure,
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strengthening the quay in hydrotechnical construction.
Building:
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temporary or permanent construction consisting of longitudinal elements, bruses (sheet piles),
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types of sheet piling:
- wooden,
- steel,
- reinforced concrete,
- PVC.
Production technology:
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sheet piles sink into the ground closely one next to the other, so that the whole is a tight plate loaded with horizontal plates sometimes also with vertical forces,
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steel bulkheads are used in all types of soils,
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ways of introducing walls into the ground:
- dynamic by using hydraulic vibrators,
- dynamic by using hammers with high impact energy,
- static by pressing the dirt into the ground, -
sheet piling can be cantilever, expanded and anchored by ground anchors,
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making ground anchors:
- drilling a hole,
- insertion into the hole of the tendon,
- injection on the anchor's supporting section,
- cable tension,
- completing the injection.
STEEL TILE PROFILES.
5. SLOT WALL.
Application:
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deep intermediate foundations,
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retaining structure protecting foundation excavations, slopes, etc.,
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protection of the excavation and external walls of the underground part of the building.
Building:
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reinforced concrete structure,
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thicknesses: 60, 80, 100, 120 and 150 cm.
Production technology:
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structure formed in soil gaps, whose stability during digging is ensured by bentonite suspension,
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during the construction of the underground, the wall can work as a support, or at a significant depth of the excavation, be secured with ground anchors or steel struts.
Bibliography:
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Collective work edited by Janusz Panas: A New Builder's Guide. Warsaw: Arkady, 2008, p. 112. ISBN 978-83-213-4247-4.
