Water Circulation in Rocks (eBook)

Laura Scesi is Professor of Applied Geology at the Polytechnic University of Milan. She published about 70 papers and 4 books on protection and optimization of natural resources, technical, geological and hydrogeological investigations for projects, hydraulic circulation in rocks, landslides and risk analysis, underground excavations.Paola Gattinoni is Researcher in Applied Geology at the Polytechnic University of Milan. She authored about 40 papers on landslides and groundwater modelling, geological, technical and statistical analysis for hydrogeological setting and rock mass characterization, geological and hydrogeological risk assessment, water circulation in fractured rocks.

Contents 4
1 Introduction to Water Circulation in Rocks 7
1.1 General Observations 7
1.2 Origin of Discontinuities 8
1.3 Features of Discontinuities 9
1.3.1 Orientation 10
1.3.2 Degree of Fracturing 12
1.3.3 Persistence 14
1.3.4 Aperture and Filling 15
1.3.5 Roughness 16
1.3.6 Weathering 18
1.3.7 Moisture Conditions and Seepage 18
1.4 Graphical Representation of Discontinuities 19
1.4.1 Equal Areal Projections 20
1.4.2 Equal Angle Projections 22
1.5 Basic Elements for Hydrogeological Conceptual Model Definition 25
1.5.1 The Work Scale 27
1.5.2 Elementary Representative Volume 28
1.5.3 Changing of Fracturing Degree with Depth 29
1.6 Probabilistic Generation of Discontinuity Network 29
2 Hydraulic Conductivity Assessment 34
2.1 Introduction 34
2.2 Deterministic Methodologies 34
2.2.1 Hydraulic Conductivity Along a Single Fracture 34
2.2.2 Hydraulic Conductivity Along a Fracture System 37
2.2.3 Hydraulic Conductivity Tensor 38
2.2.4 Equivalent Hydraulic Conductivity 40
2.3 Probabilistic Methodologies: Percolation Theory 41
2.4 In Situ Tests 45
2.4.1 Lugeon Tests 46
2.4.2 Hydrogeochemical Methods 47
2.4.2.1 Traditional Geochemical Methods 47
2.4.2.2 Methods with Artificial Tracers 48
2.4.2.3 Isotopic Methods 49
2.4.3 Hydraulic Tests in Double-Porosity Aquifers 49
2.4.4 Hydraulic Tests in Anisotropic Aquifers 51
3 Influence of Joint Features on Rock Mass Hydraulic Conductivity 54
3.1 Introduction 54
3.2 Influence of Joint Roughness 54
3.2.1 Effects of Roughness on Hydraulic Conductivity of a Single Joint: Theoretical Analysis 55
3.2.2 Effects of Roughness on Hydraulic Conductivity of a Single Joint: Experimental Checking 58
3.2.3 Effects of Roughness on Rock Mass Hydraulic Conductivity 61
3.3 Influence of Joint Aperture 63
3.3.1 Changes in Aperture with Depth 64
3.3.2 Changes in Aperture with the Stress Field 68
3.4 Influence of Joint Spacing and Frequency 72
3.5 Joints Interconnection 74
4 Main Flow Direction in Rock Masses 78
4.1 Introduction 78
4.2 Anisotropy of the Fractured Medium 78
4.3 Main Flow Direction in Fractured Media 81
4.4 Non-saturated Medium 82
4.5 Non-saturated Medium: Main Flow Direction with an Impermeable Layer 86
4.6 Saturated Medium 87
4.6.1 Known Hydraulic Gradient 88
4.6.2 Unknown Hydraulic Gradient 89
5 Methods and Models to Simulate the Groundwater Flow in Rock Masses 91
5.1 Introduction 91
5.2 Basic Elements of a Modeling Approach 91
5.2.1 Definition of the Conceptual Model 93
5.2.2 The Model Project 94
5.2.3 Choice of the Numerical Code 94
5.3 Darcys Model 95
5.4 Discrete Models 97
5.5 Dual Porosity Models 101
6 Case Histories 104
6.1 Groundwater Flow and Slope Stability 104
6.2 Evaluation of the Hydrogeological Risk Linked with Tunneling 111
6.2.1 Reconstruction of the Groundwater Flow 113
6.2.2 Estimation of the Tunnel Inflow 114
6.2.3 Delimitation of the Tunnel Influence Zone 119
6.2.4 Hydrogeological Risk Analysis 126
6.3 Hydrogeological Risk Linked with Road Construction 130
6.4 Mountain Aquifer Exploitation and Safeguard: Eva Verda Basin Case Study (Saint Marcel, Aosta Valley, Italy) 138
6.4.1 Hydrogeological Reconstruction 141
6.5 Stochastic Groundwater Modeling for the Drying Risk Assessment 147
6.5.1 Hydrogeological Setting of the Study Area 148
6.5.2 Groundwater Model of the Nossana Spring 150
6.5.3 Factors Involved in the Depletion Curve 154
6.5.4 Drying Risk Assessment 156
References 158
Index 166