Soil & Site Evaluation & Excavation (2024-25 Sem 1)

A bore hole is a deep, narrow hole drilled into the ground to obtain information about the subsurface conditions.

Bulk excavation stands for excavation in large quantity, with substantial vertical and/or horizontal spans.

Excavation is one of the most unpredictable processes in terms of time fluctuation (causing delays), cost (overruns), and site safety.

An initial survey of the site to gather visual information and assess conditions before detailed investigations.

The types of excavation can be broadly classified into five categories: Stripping top soil, Reduced-level excavation, Bulk excavation, Trench excavation, and Hole, pit, or tunnel excavation.

Shoring is a support system used to prevent soil collapse during trench excavation, especially when the depth is 1.5m or deeper.

A preliminary assessment of existing information and data related to the site before physical investigation.

Trial pits are normally dug to a depth of 4 to 5 metres.

A Shallow trial pit is a method of soil investigation that involves digging a small pit to examine the soil layers and conditions at shallow depths.

Excavation is a major part of the construction process that, while not directly related to the final products, occupies a substantial amount of time and is vulnerable to time fluctuations and site safety issues.

The Angle of Repose is the steepest angle at which a sloped surface formed of a particular material is stable, representing the balance between gravitational forces and friction.

The excavation of a pit is usually for the purposes of site investigation (trial pit), manhole construction, and caisson construction. It can be carried out manually or by purposely made mechanical plant.

Puncheons are vertical supports used in excavation to provide stability and support to the structure.

A bore hole is a deep, narrow hole drilled into the ground to obtain soil or rock samples for geological and hydrological analysis.

Shoring materials can be timber (timbering or planking) or steel (sheet pile).

A bore hole is a deep, narrow hole drilled into the ground to obtain soil or rock samples for geological and hydrological studies.

Rotary drilling is a method where a drill bit or casing shoe is rotated at the bottom of the borehole to penetrate the soil.

Proper shoring is necessary because it is often not possible to maintain the cut of excavation below its angle of repose, which can lead to soil collapse.

Struts are diagonal supports used to brace walls or other structures in excavation to prevent collapse.

To assess the suitability of the site.

Flying shoring is a type of shoring that provides support without being directly connected to the ground, often used in complex excavation scenarios.

Excavated top soil should not be reused for backfilling due to its unsettled nature, which can damage the structure.

Mechanical auger is a powered tool used for drilling into the soil to obtain samples and assess soil conditions.

A Hollow Barrel Sampler is a type of soil sampling tool used to collect undisturbed soil samples from various depths for analysis.

The two stages of Site Evaluation are Site Investigation and Soil Investigation.

Key components of a Soil Investigation Report typically include site description, soil profile, laboratory test results, groundwater conditions, and recommendations for foundation design and construction methods.

In most circumstances, mechanical plants have to be adopted, and staging of excavation may be necessary.

In Hong Kong, sheet pile is commonly adopted as the shoring material.

The process of removing the topmost layer of soil, which may contain plant and animal materials that can contaminate the structure to be erected.

A sole piece is a horizontal member placed at the bottom of a support system to distribute the load over a larger area.

A Hollow Barrel Sampler is a type of soil sampling tool used to collect undisturbed soil samples from various depths for geotechnical investigations.

Walings are horizontal members used in excavation support systems to connect vertical supports and distribute loads.

A comprehensive assessment that includes ground (soil) investigation, topographic and hydrographic surveys, and special studies.

Investigation of the soil and rock below the surface, and to detect any water that may be present in the soil.

The depth of over site excavation is usually prescribed by the engineer based on the results of the soil and site investigation.

The Angle of Repose for wet clay is 16 degrees.

A classification of mechanical plants used in excavation that remains stationary while performing excavation tasks.

The amount of water contained in the soil, expressed as a percentage of the dry weight, which influences soil behavior and plant growth.

A mechanical plant used in moving excavation, designed to load materials onto trucks or other vehicles.

Site Evaluation is the process of obtaining information about the soil before any construction or design of construction commences.

A Soil Investigation Report is a document that presents the findings of soil testing and analysis conducted at a specific site, detailing the soil properties, conditions, and recommendations for construction or land use.

Excavation is involved in foundation and basement construction, as well as in slope stabilization works.

The five categories of excavation are: 1. Stripping top soil (organic matters), 2. Reduced-level excavation, 3. Bulk excavation, 4. Trench excavation (laying utilities pipes), 5. Hole, pit, or tunnel excavation.

Site Reconnaissance is a site visit and visual inspection to assess various aspects of the site and soil, including existing slopes, structures, surface conditions, and drainage patterns.

The level formed after over site excavation is also called the formation level.

The process can be carried out by manual excavation or by using excavation machines like scrappers or bulldozers.

Trench excavation is usually found in pipe laying and cables installation works.

Adequate soil support and railings along excavation edges are necessary to protect workers from hazards such as soil collapse and falling into the excavation pit.

To determine the changes that may arise in the ground and environments, and the effect of such changes on the works, on adjacent works, and on the environment in general.

A Permeability test is a laboratory or field test that measures the ability of soil to transmit water, which is crucial for understanding drainage and stability.

The strength of soil measured directly at the site, which is essential for evaluating its load-bearing capacity.

A type of mechanical plant used in moving excavation, equipped with a broad, flat blade for pushing earth.

Soil Investigation is the process of collecting information about soil properties.

A Trial Pit is an excavation method used to investigate the subsurface conditions of a site, allowing for the observation and sampling of soil and rock layers.

The extent of the soil investigation depends on the character and variability of the ground (soil) and ground water, the type of project, and the amount of existing information.

Rotary drilling does not remove and disturb as much soil as trial pits do, allowing for less disruption of the surrounding area.

In deep pit excavation, a higher degree of safety is required, especially in manually operated excavation, such as hand dug caissons.

Major risks include disturbance of soil stability, worker safety hazards such as soil collapse and falling persons, risks to machines and vehicles falling into the excavation pit, soil movement damaging nearby structures and utilities, and potential landslides if the work area is near a slope.

To enable an adequate and economic design to be prepared.

Imported soil may be used for backfilling because a construction site in Hong Kong is usually congested, making it difficult to store excavated soil with proper protection against contamination.

A list of recommended information for a Desk Study can be found in BS5930.

A Hollow Barrel Sampler is a type of soil sampling tool used to collect undisturbed soil samples from various depths for geotechnical investigations.

A Trial Pit is an excavation method used to investigate the soil and subsoil conditions at a specific site, allowing for the assessment of soil properties and the presence of groundwater.

A Soil Investigation Report is important because it provides essential information about soil conditions that can affect the safety, stability, and suitability of a construction project, helping to prevent structural failures and costly repairs.

Trial pits are excavations, usually machine-dug, used for ground investigation and soil inspection, particularly for low-rise buildings.

Struts provide lateral support to the shoring, helping to maintain stability during excavation.

The depth of top soil stripping varies from 150mm to 300mm, depending on the size of the site.

A Desk Study is a preliminary study about the site, primarily focused on collecting information from various sources such as Lease conditions, Buildings Department, Town Planning Department, Lands Department, Land Registry, and the Geotechnical Office.

The purpose of a Desk Study is to gather relevant information about a site from multiple sources to inform further investigation and evaluation.

The condition of the surface of the site, including topsoil quality and any visible signs of erosion or instability, should be observed and recorded.

The Angle of Repose for drained clay is 45 degrees.

The Angle of Repose for gravel and dry sand is 40 degrees.

A mechanical plant used in fixed position excavation, equipped with a digging bucket on a hinged arm.

A type of mechanical plant used in fixed position excavation, designed to lift and move large materials.

A Trial Pit is an excavation made to investigate the soil and subsoil conditions at a specific site, often used in geotechnical engineering.

The nature of the strata can be determined only by inspecting the excavated material brought up by the auger during the drilling process.

Walings are horizontal supports that run along the vertical excavated surfaces to provide stability to shorings.

The purpose is to provide a reference for subsequent construction work to commence.

Trial pits should be located close to the proposed foundation of the building.

Folding wedges are adjustable devices used to secure and stabilize supports in excavation systems.

To plan the best method of construction, to foresee difficulties and delays that may arise during construction due to ground and other local conditions.

The measurement of how deep the top layer of soil is, which is crucial for understanding soil health and agricultural potential.

If alternatives exist, to advise on the relative suitability of different sites.

Reduced Level Excavation is the process of excavating the over site to a specified level to create a leveled ground that serves as a reference for subsequent construction work.

Raking shoring refers to shoring that is installed at an inclined angle to provide support.

Additional assessments conducted during the construction phase to ensure that site conditions are as expected and to address any unforeseen issues.

De-watering affects soil stability by altering moisture content and groundwater levels, which can impact soil volume and increase the risk of collapse.

The Angle of Repose represents the maximum degree of angle that the soil remains stable without requiring additional support, varying for different types of soil.

The Angle of Repose is largely governed by composite soil properties, moisture content, water table, and the loading applied on the soil in adjacent areas.

A potential consequence of Excavation work near a slope is a landslide, which can pose significant risks to safety and stability.

The mass per unit volume of a soil layer, which affects its stability and compaction properties.

Investigation of the site on the surface and its surrounding environment.

Tasks include inspecting existing slopes, retaining walls, surface drainage patterns, vegetation, and adjacent structures, as well as conducting local inquiries and checking for obstructions.

A Deep trial is a soil investigation technique that involves excavating deeper pits to assess soil characteristics at greater depths.

The cost of site investigation typically ranges from 0.5% to 5% of the total project cost, depending on the size of the project.

The operation of trench excavation is usually in one of the following three ways: full depth, full-length excavation; full depth, successive stages of excavation; stage depth, successive stages of excavation.

Soil movement can cause damage to nearby structures and underground facilities, including utilities and transportation systems.

Compacting is usually carried out by mechanical equipment such as pneumatic compactors or rollers.

The Angle of Repose for wet sand is 20 degrees.

The number of trial pits depends on the development scale, the variability of soil content, and the risks the developer could tolerate.

Hand auger boring is a manual method of drilling into the ground to collect soil samples for analysis.

The excavated top soil should be disposed of at approved landfills.

The classification of different soil types found within each layer of strata, which affects drainage, stability, and vegetation.

A type of mechanical plant used in fixed position excavation, designed for digging and moving earth.

The leveling of the site may involve both cut and fill operations.

The ideal backfilling materials are the materials originally excavated, unless they are contaminated.

The typical specification requires compacting to be carried out in layers of 150mm to 200mm in thickness.

The depth at which the soil is saturated with water and how this level changes over time, which is critical for drainage and foundation design.

Inspecting existing slopes is crucial to identify potential issues such as gradient stability, tension cracks, and overall slope integrity, which can affect site safety and suitability.

Local enquiries help gather information about the site history, conditions, and any potential hazards from local inhabitants, enhancing the understanding of the site.

Departments involved in a Desk Study include the Buildings Department, Town Planning Department, Lands Department, Land Registry, and the Civil Engineering & Development Department.

The arrangement and characteristics of different soil layers, including their thickness and depth, which are important for geological and engineering assessments.

A classification of mechanical plants that can move while performing excavation tasks.

A type of mechanical plant used in fixed position excavation, which uses a bucket attached to a cable to dig and move material.

Wash boring is a drilling technique that uses water to remove soil cuttings and facilitate the collection of soil samples.

A mechanical plant used in moving excavation, specifically designed for digging trenches.

The characteristics of the underlying soil layers, including texture, composition, and behavior under load, which influence construction and land use.

A mechanical plant used in moving excavation, designed to scrape and transport material over short distances.

A type of mechanical plant used in moving excavation, primarily used for leveling and grading surfaces.