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Construction of an embankment
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1. Geotechnical Investigation
A geotechnical investigation is a fundamental first step in any construction project. This phase involves all necessary soil studies and analyses to provide critical data for engineering and design.
Upon completion, the geotechnical firm will submit a final report. This report must provide comprehensive technical details, conclusions, and actionable recommendations. The report shall include:
A. Descriptive Summary
A complete summary of all field operations (e.g., borings, test pits) and laboratory tests performed. This section must include a site plan or sketch that clearly indicates the location of all exploratory tests.
B. Summary of Results
A detailed presentation of all data and results, specified in graphs, tables (numerical values), and a clear narrative. This must include:
Soil classification according to the Unified Soil Classification System (USCS).
Mean and recommended soil resistivity values (for grounding and corrosion analysis).
All other relevant engineering parameters, such as the modulus of subgrade reaction (dynamic ballast coefficient).
C. Final Recommendations
A concluding report with clear recommendations for the project's design and construction. These recommendations must provide the technical specifications required for the project, covering the following key areas:
Earthwork Operations: Recommendations for excavation methods, stable slope angles, and requirements for any necessary dewatering systems.
Foundation Recommendations (Shallow & Deep):
Shallow Foundations: Recommended foundation types, allowable soil bearing capacity at various depths, coefficients of friction, and settlement estimates.
Deep Foundations (Piles): Recommended pile types, estimated end-bearing capacity, and skin-friction (shaft) capacity.
Soil and Water Aggressiveness: An analysis of the soil and groundwater's potential to corrode or degrade foundation materials. This will include specific recommendations for the appropriate type of cement (e.g., Type II, Type V) to be used in foundations.
Water Table Analysis: Determination of the depth, location, and potential seasonal variations of the groundwater table.
Structural Fill:
Analysis of the suitability of on-site soils for use as structural fill.
If on-site material is unsuitable, specifications for imported fill material.
Detailed compaction requirements, including applicable standards (e.g., ASTM), required Proctor density, and minimum load-bearing values (e.g., CBR). These parameters must be met by all on-site or imported fill material.
2. Site Survey and Hydrological Analysis
This phase establishes the existing conditions of the site and is typically performed before major field work or site clearing begins.
A. Topographic Survey
The Contractor must conduct a comprehensive topographic survey of the entire property, including all access points and external drainage features. This survey will establish:
Permanent benchmarks (fixed leveling points).
Reference axes and a site grid (e.g., 20m x 20m) that will be used for all project layouts.
B. Hydrological & Flood Analysis
In addition to the survey, a hydrological analysis is required to determine the site's flood risk. This study must use historical data, statistics, and on-site information to establish design flood levels, ensuring that future climatic events do not disrupt the service continuity of the completed facility.
C. Site Plan
The survey and grid will be used to create the base site plan. This plan will be the foundation for all subsequent design, including:
Clearing and grubbing (deforestation).
Site grading and embankments.
Stormwater drainage conduit and systems.