Dam Foundation Research Articles

Real-time identification of foundation damage in high-Pile Wharves: Nonlinear feature change point analysis in dynamic characteristics under wave excitation

Waves are a common excitation form for wharves. The responses of pile foundation in high-pile wharves under such excitation exhibit pronounced nonlinear and non-stationary characteristics, compromising the robustness of damage detection methods. To address this challenge, this paper first introduces a method using Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) and spectral feature analysis, aimed at extracting the overall characteristic sub-signals to resolve multi-type signal aliasing. Secondly, the Generalized Autoregressive Conditional Heteroskedasticity (GARCH) model is employed to isolate the nonlinear dynamic features of the response under wave excitation. Thirdly, the Weighted Residual Cumulative Sum (WRCUSUM) method is developed to monitor changes in response characteristics online, thereby enabling the identification of damage occurrence and its timing. Further, the efficacy of the proposed method has been validated through high-pile wharf experiments conducted at various damage levels. This approach not only offers a novel solution for online damage detection under wave excitation but also introduces a new strategy for non-destructive testing across offshore engineering applications.

Identifying Suitable Dam Locations in Al Dinder: Integrating GIS, Remote Sensing, and Hydrological Factors

This study evaluates the suitability of dam site locations in the Al Dinder region of Sudan using a GIS-based approach and weighted overlay analysis. Five key criteria were assessed: Stream Order, Slope, Soil Type, Precipitation, and Land Cover. Each criterion was analyzed to determine its impact on selecting optimal sites for dam construction. The results reveal that fourth-order streams offer the highest suitability due to their larger flow capacity, covering 11.4% of the area, while first-order streams, accounting for 48.9%, are less suitable. Slope analysis shows that 99.52% of the region features gentle slopes (0-5°), which are ideal for dam construction. Soil type analysis identifies Gleysols as the most favorable for dam foundations, covering 86.1% of the area. Precipitation levels, particularly in areas receiving 1200-2200 mm of rainfall, are deemed highly suitable for dam operations. The study further reveals that 96% of the land cover consists of barren land, which is advantageous for construction due to minimal land-use conflicts. A detailed cross-sectional profile analysis of six proposed dam sites identified Dam 5 as the most suitable location, offering stable terrain, a consistent cross-section, and favorable hydrological conditions. Other sites, such as Dam 1 and Dam 6, show promise but require additional engineering modifications. The study’s findings contribute valuable insights into sustainable water resource management and infrastructure development in regions with similar environmental conditions. Key recommendations include further feasibility assessments, environmental impact analyses, and consideration of the social and economic benefits of dam construction.

A Comparative Study of Different Blasting Excavation Methods of the Gentle Slope in High Dam Foundation

A Comparative Study of Different Blasting Excavation Methods of the Gentle Slope in High Dam Foundation

Physical Test and Numerical Analysis of Damage Mechanism of Rocky Foundation with Parallel Structural Surfaces

The growth of rock structural surfaces makes the deformation and stability analysis of rock pits more complex and challenging than that of soil pits. To investigate the damage mechanism of this foundation and provide ideas for foundation support, the paper constructed a simplified model by approximate plane analysis and dimensionless analysis of the similarity principle. The physical model was constructed from a mixture of materials, and then foundation excavation and loading tests were completed. The strain value of the strain gauges increased in stages in the range of 0–250. Excavation of the structural surface resulted in an increased number of deformation mutations. This type of rocky foundation damage underwent three stages: overburden crack development, cumulative deformation of the S-S, and collapse of the sliding body. Furthermore, numerical simulations corresponding to the physical model tests were set and used to validate and complement the physical tests. When the line loads reached 70.83 kN/m and 127.5 kN/m, the plastic zone of the structural surface was completely penetrated and the sliding body collapsed. The results of the studies can serve as a useful reference and guide for the excavation and support design of real-world rock foundation projects that are similar.

Evaluation of the Stability and Suitability of Ashebeka Dam Foundation and Reservoir Area, Central Ethiopia

Evaluation of the Stability and Suitability of Ashebeka Dam Foundation and Reservoir Area, Central Ethiopia

Suffusion characteristics of a heterogeneous dam foundation with a cut-off wall of stochastic defects

Natural alluvial foundations are inherently heterogeneous. To enhance seepage safety, a cut-off wall is commonly embedded in a dam foundation. However, walls can also have stochastic defects. The dual uncertainties arising from soil heterogeneity and wall defects pose significant challenges for seepage safety evaluation. In this study, systematic numerical simulations were conducted on an internally unstable dam foundation based on a four-constituent mixture framework. Soil heterogeneity was characterized by stochastic initial hydraulic conductivity and initial fines content. An erosion model, specifically incorporating the influence of overburden pressure, was employed to quantify suffusion. A probabilistic assessment utilizing Monte Carlo simulations revealed that suffusion in heterogeneous fields could be more severe than that in homogeneous fields. Various combinations of stochastic soil properties and defect locations can result in substantial disparities in seepage and erosion fields. The mean values of the total flux and the fines eroded ratio are insensitive to the spatial variation length, while their deviations increase with increasing spatial variation length, leading to larger uncertainties in the leakage channel morphology. For highly heterogeneous alluvial foundations with large spatial variations, conventional seepage and suffusion analyses that rely on homogeneous assumptions may considerably underestimate the internal erosion risk.

Engineering geological evaluation of Bowa Dayole dam site, North Shewa Zone, Oromia, Ethiopia.

Developing nations like Ethiopia face food and water shortages due to weather and droughts. The Bowa Dayole masonry gravity dam is expected to irrigate farmland downstream. Despite this, the engineering geology is complicated by the presence of highly fractured and weathered aphanitic basaltic rock, along with a weak unwelded to welded tuff rock mass in the dam foundation. An engineering geological evaluation of the dam site and of the reservoir rocks and soils has addressed these challenges. Geological mapping, discontinuity surveying, core drilling, permeability testing, and laboratory analysis were used to achieve these goals. As the study area's main lithological units, geological mapping revealed units such as colluvial and alluvial deposits, aphanitic basaltic rock, and tuff units with varied degrees of fracturing and weathering. The unconfined compressive strength of these rocks' ranges from 0.16MPa to 146.88MPa, as determined from the Point Load Index Test, varying from very low to high strength. The Rock Quality Designation analysis indicated poor to excellent rock mass quality. The packer test revealed that the hydraulic conductivity with representative Lu values of less than 1 which indicated that excessive leakage at the dam site would not be expected. The allowable bearing capacity of aphanitic basaltic rock at the abutment and at the foundation was 0.54MPa-6.77MPa and 0.1MPa-18.86MPa, respectively. At the dam's foundation, tuff rock had an allowable load-bearing capacity of 0.037MPa-0.11MPa. Due to the poor bearing capacity of the tuff rock unit under the dam foundation, uniform settlement was expected, but even load distribution by the aphanitic basaltic rock and adequate foundation construction can mitigate this issue.

Study on Mechanical Characteristics of Discontinuous Cut-Off Wall of Dam Foundation Based on Plastic Damage Calculation Method

Dam foundations are prone to leakage damage after being exposed to long-term water action, which seriously affects the operation safety of the dam. At present, concrete cut-off walls serve an important means of anti-seepage for dam foundations. However, due to construction challenges, the cut-off wall needs to be poured segment-by-segment during the construction process, and the joints between adjacent segments become weak parts for seepage prevention. Therefore, it is crucial to clarify the stress state of segmented discontinuous concrete cut-off walls. Based on the Lee-Fenves framework and the tension–compression constitutive relationship of fracture energy, a plastic damage calculation method was established in this paper to characterize the mechanical behavior of discontinuous cut-off walls. The method was then used to analyze the mechanical performance of discontinuous walls with segment joints containing slurry cake. The research results showed that compared to the continuous cut-off wall, the vertical settlement in the middle part of the discontinuous cut-off wall increased by 5.8%, and the displacement along the river flow direction decreased by 35.3%. As the wall segment width decreased, the joint opening and the degree of tensile damage were reduced accordingly, while the compressive damage in the middle and lower parts of the wall was intensified. As the wall depth decreased, the constraints and load on the bottom of the wall showed obvious changes, leading to a reduced stress and damage level of the wall. The findings provide reference for the design and safety control of cut-off walls.

Assessment of foundation damage during earthquakes using acoustic emission monitoring: An experimental study on the shaking table test

Assessing structural foundation damage following an earthquake is critical for safety evaluation. However, assessing the damage to pile foundations with traditional visual inspections and non-destructive testing methods is challenging. This study evaluated the use of acoustic emission (AE) monitoring for damage detection and location in foundation structures during earthquake simulations by conducting shaking table experiments. Scaled models of foundation structures with and without surrounding soil were used in the experiments, and the performance of the AE monitoring system was evaluated by comparing the AE parameters via visual inspection. The experimental results showed that the AE monitoring system could effectively predict the initiation of cracks in foundation structures that experienced an earthquake. In addition, an appropriate filtering criterion for the shaking table experiments was established based on the AE characteristics of the foundation structures during the earthquake simulation, thereby improving the performance of the AE monitoring system for damage location. Consequently, this study contributed to a better understanding of the applicability of AE monitoring systems to foundation structures during earthquakes.

The Behavior of Pile Foundation in Liquefiable and non-Liquefiable Soil Layers Considering Soil-Pile-Structure Interaction

Abstract Liquefaction has emerged as a primary cause of damage to civil engineering structures in seismically active places. Deep foundation damage from liquefaction can be quite damaging. The seismic behavior of pile foundations immersed in the earth under seismic loads is presented in this work. Bending moments, shear forces, and lateral displacements along the pile’s depth before and after liquefaction have been compared. The soil, pile, and structure interaction was analyzed using SAP2000 finite element (FE) software. The inertial load from superstructure vibrations on piles embedded in the soil layer was calculated using three-dimensional (3D) finite element (FE) modeling. The study examined the effects of multiple factors on the pile response, including the seismic parameters and soil conditions around the pile. According to the research findings, in proportion to the increase in seismic parameters and the transition from non-liquefaction to liquefaction of the surrounding soil, piles experience an increase in internal forces.

Pseudo-damage simulation and CNN deep learning for damage identification of submerged structure-foundation systems

Autonomous damage identification of submerged structure-foundation systems is challenging due to the difficulty of acquiring damage-induced system responses for training deep learning models. In this study, a novel approach integrating pseudo-damage simulation and convolutional neural network (CNN) deep learning is proposed for damage identification in the submerged structure-foundation system. Pseudo-damage simulation is a technique to generate equivalent damage conditions in inaccessible submerged sub-systems for training deep learning models. The following approaches are implemented to achieve the objective. Firstly, a scheme of pseudo-damage simulation for 1-D CNN deep learning is designed for the caisson-foundation system. Secondly, a vibration monitoring method using pseudo-wave-impulse excitations is designed for the caisson-foundation system. Thirdly, 1-D CNN models are trained for individual caisson units to predict the location and size of foundation damage by vibration signals out of a series of pseudo-damage cases. The 1-D CNN models demonstrate accurate performance in handling untrained scenarios. Experimental results validate the effectiveness of the proposed approach in achieving high accuracy for identification of the foundation damage.

Model for quality classification of dam foundation rock mass based on Gaussian function weighted KNN algorithm and its application

Model for quality classification of dam foundation rock mass based on Gaussian function weighted KNN algorithm and its application

A novel method combining strata movement and UAV infrared remote sensing technology to evaluate mining ground damage

Mining-induced ground fissures are common problems associated with mining damage in shallowly buried coal seams in the western mining area of China. To evaluate the surface mining damage of the 12203 working face of the Huojitu Colliery in Shendong mining area, low-altitude infrared aerial surveys were conducted on the ground at the static fissure area (O-A1) and the dynamic fissure area (O-A2) of the working face. The temperature evolution patterns of fissures, sand and plants in the infrared images were analysed. The relationship between overburden fractures and surface fissure temperature was revealed, and the influence range and temperature self-healing period of the surface affected by underground mining were determined. The results indicated that underground mining could lead to a decrease in the ground temperature above the working face. The surface temperature evolution can be divided into three zones: a temperature stabilization zone before mining, a temperature cooling zone during mining, and a temperature recovery zone after mining. The temperature of sand and plants above the working face exhibited quadratic curve changes in O-A1 and O-A2, respectively. The length of the temperature reduction zone affected by mining is 40 m in O-A2, and 46.8 m in O-A1. The temperature recovery periods of ground fissures in O-A1 and O-A2 were 4.0 and 4.6 d, respectively. These findings could provide a basis for evaluating mining ground damage.

Inversion method for working behavior of prestressed anchor cables in dam foundation driven by structural health monitoring data

Accurate knowledge of the working behavior of prestressed anchor cables is essential to ensure the long-term safe operation of dams. However, due to the lack of effective monitoring means, it is hard to analyze the working performance of anchor cables, and there is still a lack of methods to accurately quantify the anchorage effectiveness of prestressed anchor cables in actual hydraulic engineering projects. To solve this problem, this paper presents an inversion method to accurately quantify the behavior of prestressed anchor cables in dam foundations using structural health monitoring data. Firstly, Ensemble Empirical Mode Decomposition (EEMD) and Singular Spectrum Analysis (SSA) are used to denoise monitoring sequences. Secondly, the hydraulic pressure deformation component is separated by constructing a statistical model reflecting the relationship between dam deformation and environmental factors. Meanwhile, a three-dimensional finite element model (FEM) of the dam and its foundation is established in which the water load and anchoring force are applied step by step to simulate the deformation values of the dam under different combinations of working conditions. And a BP neural network is used to fit the finite element forward process. Finally, the inferred values of the anchorage force are derived by comparing the deformation separated by the statistical model with the deformation calculated by the FEM. In order to minimize the fitting difference of the two series of deformations, an improved grey wolf optimization algorithm (IGWO) is introduced to optimize the inverse calculation. The method is applied to a multiple arch dam foundation anchorage project, and its feasibility and effectiveness are verified. The proposed method is capable of providing effective support for ensuring the safe service of prestressed anchor cables of dams.

Ground Deformation and Damage Assessment using SAR Observations: A Case Study of Hinatuan, Philippines in the 2023 Surigao Del Sur Earthquake

Abstract. Earthquakes are among the major hazards that lead to economic loss every year. Rapid damage assessment is essential for a more efficient disaster response. The 2023 Surigao del Sur earthquake in the Philippines with moment magnitude (Mw) 7.4 occurred on December 2, 2023, with Hinatuan as the nearest municipality located 12 km south of the epicenter. Thus, this study examined the co-seismic impacts in Hinatuan using Synthetic Aperture Radar (SAR) observations. Using phase interferometry and displacement maps to estimate the ground surface deformation, results show that the phase interferograms, Line-of-sight (LOS) displacements, and vertical displacements were consistent, with most of Hinatuan experiencing an uplift of up to 7.2 cm. In contrast, subsidence as low as –9.0 cm was observed in some isolated areas. The damage assessment conducted through change detection analysis revealed 6.15 ha (6.4%) of built area out of the total 84 ha was significantly damaged. The damage mainly occurred in the uplifted regions between 0 to 5 cm. Building codes, land-use planning, and risk management and assessment can be improved and strengthened with these findings for a more earthquake-resilient community. The findings will be a basis for disaster risk reduction and management actions. These may, furthermore, serve as a reference for the development planning of local government units, especially for urban and built-up areas. These can also be used in developing Information, Education, and Communication (IEC) materials and advisory for residents in Hinatuan and the vulnerable adjacent regions.

Analytical Mini-Review of Different Sheet Pile Configuration Utilization for Dam Seepage Reduction and Applications on Iraqi Dams

Abstract Seepage is one of the main causes of dams and some other hydraulic structures' failure. Water movement beneath the dam’s base creates piping and uplift pressure under the structure, potentially leading to improper dam operation. This current study focuses on the utilization of a special technique to restrict the transfer of movement water via soil which includes sheet piles under the dam foundation. Sheet pile walls are interlocking pile segments that are embedded in soil to resist horizontal pressure, classified as a flexible retaining system, and capable of tolerating relatively large deformations. Sheet piles are made of various materials, such as wood, concrete, steel, and aluminum, which are suitable for different applications. The role of seepage can be affected by the cutoff utilization. In this study, some Iraqi dam issues due to seepage are explained, also the geological stratum beneath the dam is briefly discussed. the potential use of sheet piles with different configurations has been reviewed to detect the optimum situation for seepage parameters reduction based on their numbers, interval distances, inclinations, and places. Keywords: Seepage, sheet piles, impermeable foundation, Iraqi dams’ issues, and geological stratum.

Geotechnical and geological reconnaissance observations of the 6 February 2023 Türkiye earthquakes

The 6 February 2023 Türkiye earthquakes and the accompanying aftershocks were a once-in-a-century catastrophe that has greatly impacted Türkiye and Syria. The repercussions of these events will have a lasting effect on the entire region. This article documents the geotechnical and geological observations performed by GEER (Geotechnical Extreme Events Reconnaissance) immediately following the events. Observations of ground damage, including surface fault rupture, liquefaction and lateral spreading, landslides and rock falls, and foundation failure of buildings, dams, and other civil infrastructure, are described herein. This article summarizes the key findings that were originally reported in the joint GEER-EERI (Earthquake Engineering Research Institute) reconnaissance report. The goal of these reconnaissance efforts is to document perishable data and disseminate it widely so that lessons can be learned from these events.

Integrating analytical and machine learning approaches to simulate and predict dam foundation stress and river valley contraction in a large-scale reservoir

Integrating analytical and machine learning approaches to simulate and predict dam foundation stress and river valley contraction in a large-scale reservoir

3D seismic bearing capacity of rectangular foundations near rock slopes using upper bound method

The analysis of foundation's bearing capacity is generally conducted under the assumption of plane strain. However, the damage of rectangular foundation usually presents obvious three-dimensional (3D) effect. This article considers this 3D effect, which, for the first time, provides a theoretical framework for assessing the bearing capacity of rectangular foundations placed on rock slopes under seismic condition. In order to apply the kinematic method of limit analysis, a new 3D kinematically admissible collapse mechanism is first constructed. Owing to the point-to-point discretized technique, this 3D mechanism can avoid complex surface integration and effectively reduce spatial coordinate iterative calculations while maintaining high accuracy. The pseudo-static method is adopted to simulate the effects of earthquakes. Generalized multi‑tangential technique is employed to derive the Mohr-Coulomb constants from Hoek-Brown criterion. The comparison between the present results and results of previous literatures proves the validity of the theoretical framework in this paper. Shape factor and reduction factor are introduced in the parametric study, showing that the 3D effect is more obvious when the rectangular foundation aspect ratio is reduced. As the rectangular foundation location moves away from the slope, its bearing capacity gradually converges towards that of the horizontal foundation. The critical collapse mechanism is also explored, demonstrating that the collapse extent expands with increasing internal friction angle of the rock.

Ground failures and foundation performances in Adıyaman–Gölbaşı following the 6 February 2023 Kahramanmaraş–Türkiye Earthquake Sequence

The 6 February 2023 Kahramanmaraş–Türkiye earthquake sequence (M7.8 and M7.6) presents an exceptional opportunity to investigate both the effects of local soil conditions on damage patterns under strong shaking conditions and the performance of building foundations in areas that experienced ground failure. The significant ground failure and structural damage in Adıyaman–Gölbaşı triggered an intensive series of detailed reconnaissance and field surveys. This article aims to present the resulting database of observations on ground failures, building, and foundation performances. The field reconnaissance of ground failures and their effects on building performances involved aerial and walk-down surveys, including high-quality photographs taken across the town. In addition, data on building damage statistics compiled by the Ministry of Environment, Urbanization, and Climate Change were accessed and analyzed. The subsurface characteristics of the town were characterized using available data from pre-earthquake site investigation campaigns employed for town planning purposes. It is concluded that the ground failures in the town primarily resulted from soil liquefaction and cyclic softening. Most of the poor building and foundation performances and ground failures were documented in the northern part of Atatürk Boulevard, closer to the lake of Gölbaşı, where soil site characteristics were unfavorable. This revealed once again the significant effects of local soil site conditions, particularly soil liquefaction, on the intensified ground failures, foundation, and structural damage levels.