Applied Engineering Geology

Introduction

Applied Engineering Geology deals with the application of geologic principles and knowledge to human works, notably civil and mining engineering.
This branch of geology focuses on the geotechnical design of man-made structures and excavations, and plays a key role in mitigating geohazards.

Prior to any construction or excavation project, a comprehensive geological field investigation takes place.
This includes topographic mapping, satellite imagery analysis, aerial photography interpretation, and in some cases, geophysical surveys.
The purpose is to identify and evaluate geologic features like rock and soil types, slopes, structures, and groundwater that might affect or be affected by the coming engineering activities.

Rocks, unlike engineered materials, do not have uniform properties. Their physical properties can vary vastly depending on their mineral composition, structure, weathering state, and others.
Therefore, the physical and mechanical properties of rocks such as density, hardness, porosity, permeability, compressibility, shear strength, and tensile strength, are key components of the design and planning process in engineering projects.
Technical rock classification systems, for example, the Rock Mass Rating (RMR), can provide a simplified interpretation of these properties.

Stability is a major concern when dealing with structures interacting with rock or soil.
Evaluation of structural stability often involves the assessment of rock or soil strength, joints and fractures, groundwater conditions, stress distribution, slope, and potential for movement.
Techniques like the kinematic analysis for rock slopes and limit equilibrium methods for soil slopes can be applied in stability investigation.

Identifying potential geohazards is a crucial part of Applied Engineering Geology.
Potential hazards include geological stresses such as earthquakes, volcanoes, and tsunamis, and ground instabilities like landslides and subsidence.
It also considers human-induced hazards, including mining and tunnelling activities, and the impact of urbanisation.

Upon identifying potential geohazards, effective mitigation strategies can be planned and executed.
These strategies may involve altering construction or excavation designs, improving ground conditions with techniques like grouting or reinforcement, draining or controlling groundwater seepage, and others.
In certain high-risk scenarios, it might be necessary to relocate the proposed project to another site.

Monitoring is essential to verify the continued stability and safety of structures and sites, especially in regions susceptible to geohazards.
Technological tools for monitoring include GPS, remote sensing, and geophysical techniques among others.
Monitoring can facilitate early detection of possible issues, allowing for prompt action and minimisation of risks.

Applied Engineering Geology doesn’t operate in isolation. It works hand in hand with other disciplines such as structural geology, hydrogeology, and geophysics.
By integrating knowledge across these disciplines, a more comprehensive and accurate understanding of the geological, hydrogeological, and geotechnical environment can be achieved, which is crucial for safe and successful engineering projects.