SUBSURFACE GEOPHYSICAL EVALUATION OF ROAD FAILURE MECHANISMS IN A ROAD SEGMENT AT EKITI STATE UNIVERSITY CAMPUS

Geophysical and the geotechnical methods were used to study the site of a collapsed two-storey building in orderto determine the sequence and competence of the subsurface layers and determine the cause of the collapse of the building. The geophysical method employed the electrical resistivity method involving one dimensional (1D) Vertical Electrical Sounding (VES) and the two dimensional (2D) imaging techniques. Three VES stations were occupied using Schlumberger electrode configuration. 2D imaging data were acquired along four traverses using dipole-dipole electrode configuration. The geotechnical method involved Cone Penetration Test (CPT). CPT data was acquired at two points with the aid of 2.5 ton Dutch CPT machine. The results showed four subsurface layers based on the 1D VES results and 2D imaging results namely: topsoil, weathered layer, fractured basement rock and fresh basement rock. The topsoil resistivity varied from 116 Ωm to 191 Ωm and has thickness of about 1.5 m. It was classified as moderately competent. The second layer is weathered rock with resistivity varying between 92 Ωm and 327 Ωm and of about 8 m to 13 m thickness. This layer is also moderately competent. The third layer is fractured basement rock. It underlies the weathered rock and have resistivity varying from 391 Ωm to 405 Ωm. Its thickness varied from about 2 m to 20 m. This layer is competent. The fourth layer is the fresh basement rock having resistivity varying from 1365 Ωm to 12348 Ωm and is highly competent. The subsurface materials in the area are competent and can sustain the foundation of the building. Hence, the study concluded that the building collapse did not result from incompetent subsurface materials. Factors other than incompetent subsoil material that is human factors are believed to be responsible. This study has demonstrated the effectiveness of geophysical and geotechnical investigations in determining the competence of subsurface materials at engineering sites.

Parametric Model for Accident Prediction Along Ado Ekiti – Ikole Ekiti Road, Ekiti State, Nigeria

Road maintenance projects frequently encounter issues such as delays in completion, inadequate user satisfaction, and inconsistent quality of work. This study examined how Kenyan road maintenance projects performed in relation to Monitoring and Evaluation (M&E) procedures. This research purposed to determine the impact of M&E budget allocation on the Central region's Kenya National Highways Authority (KeNHA) road repair projects' performance. In this investigation, the guidance was drawn from the theory of constraints. This research employed descriptive survey research and targeted 24 roads under KenHA maintenance in Central region. The intended participants comprised 72 road engineers and 50 KeNHA staff from various counties in the central region. A census sample approach was employed in the study. Both closed-ended and open-ended questionnaires were used in the study. A small sample of ten road engineers working on KeNHA projects participated in a pilot study. The data was statistically analysed using SPSS version 27. The study on budget allocation in road maintenance projects found positive evaluations of budget management, with a composite mean of 4.19. Correlation analysis showed a strong positive link between budget allocation and project performance (r = 0.670, p < 0.001), while regression analysis indicated budget allocation accounts for 57.3% of performance variance (R² = 0.573). Overall, effective budget allocation for M&E activities, including training and logistics, significantly boosts project success. The study recommended that KenHA should ensure adequate allocation of M&E funds to enable training of monitoring team and for logistical support.

Effective engagement of the community in road maintenance projects promotes local needs and preferences, leading to more relevant and responsive initiatives.In particular, the community workshopscultivates a sense of ownership and collaboration among community members. This fosters trust between stakeholders and contributes significantly to the success and sustainability of road maintenance efforts. However, road maintenance projects in Kenya have continually demonstrated inadequate implementationwith delays in repairs leading to extended road deterioration and increased safety risks. The present study examinedthe effect of community workshops, as a strategy of community engagementon the implementationof road maintenance projects in South Rift Region, Kenya. The study was grounded onstakeholder theory. Adescriptive research design wasadopted. The target population consistedof 28road maintenance projectsbyKeNHA,South Rift Region.Both descriptive and inferential methods wereapplied in the analysis. In the descriptive analysis, means, percentages and standard deviations wereemployed. On the other hand, correlation and regression analysis were usedin inferential analysis. The Statistical Packages for Social Sciences (SPSS) aideddata analysis, and the findings werepresented through tables.The descriptive findings indicatedthat community workshopsplay a vital role in the implementation of road maintenance projects by Kenya National Highways Authority. Correlation analysis revealed significant positive relationships between community workshops (r = 0.744**, p = 0.000) and implementation of road maintenance projects.Regression analysis further demonstrated a strong overall relationship between community workshops and implementation of road maintenance projects. The coefficientof determination R² value of 0.554indicated that 55.4% of the variation in road maintenance project implementation is explained by community workshops. The study concludes that community workshopsenhance collaboration and coordination. Theyimprove communication, accountability, and sustained involvement, ultimately strengthening the implementation of road maintenance projects. The study recommends Kenya National Highways Authority embed community workshops into operational framework to boost stakeholder alignment, and improve implementation of road maintenance projects.

In response to the phenomenon that road maintenance construction activities may have a certain impact on passing vehicles and generate additional carbon emissions, based on the Tianjin Avenue Restoration and Maintenance Project, a recommended list of carbon emission factors is proposed. A traffic impact carbon emission calculation model is used to calculate the traffic impact carbon emissions of the supporting project, analyze the characteristics of traffic impact carbon emissions composition, and explore the hot spots of traffic impact carbon emissions of maintenance projects, propose emission reduction strategies for road maintenance engineering traffic organization.

The recent failure of building foundations such as cracks, structural differential settlements and collapse has now become a great concern to geoscientists. A new site at Ahmadu Bello University, Nigeria, was investigated to explore the suitability of the subsurface material for the foundations of buildings, identify weak zones that may be prone to subsidence and the competence to support massive structures. This investigation was achieved with 3D electrical resistivity tomography (ERT). The data were obtained using Terrameter SAS 4000 and ES 464 electrode selector equipment and processed using the RES3DINV software. Dipole-dipole configuration at electrode spacing of 5 m was used to acquire the data along six profiles laid in the study area. The results in correlation with borehole data showed that the subsurface has a minimum of three geo-electric sections. It can be concluded that the competent layer with high resistivity values (746 to 1206 Ωm) is recommended for building or high rising building foundations due to its fresh basement rock. In the topsoil, clay formation should be avoided, this is because the clay materials are subject to differential settlement or flow under pressure.

In order to solve the problem that the traditional crack image segmentation method cannot accurately extract the edge structure of road cracks, a flexible crack detection and identification system are provided. Firstly, a road crack dataset is built by processing the acquired images using the sliding window technique. A model called R2-AENet is proposed for training and testing. The model structure uses the recurrent residual convolutional neural network (RRCNN) to improve the convolutional structure and drive the accumulation of fracture features. The model decoder combines the attention-guided filtering module and the edge residuals module (ERB) better to extract the edge features of the feature map. As a result, it improves the crack segmentation performance. Finally, the research results are validated on the upgraded software platform. The experimental results demonstrate that the R2-AENet model achieves better segmentation results compared to the popular deep learning algorithm models. Evidently, the model achieves accuracy and recall of 0.982 and 0.849 on the collected dataset. Besides, the area under the curve (AUC) metric value can reach 0.992. In addition, the detection results in different data sets perform well, verifying that the model has exceptional robustness and can be applied to various environmental road inspection and maintenance projects.

Lane closure is frequently performed in the execution of the road maintenance project. It has a negative impact on road users such as the loss of vehicle operating costs and the loss of time value. Nevertheless, analysis on loss of time value in Indonesia has not been carried out. The parameter of time value for the road users was the minimum wage city/region approach. Vehicle speed of pre-construction was obtained by observation, while the speed during the road maintenance project was predicted by the speed of the pre-construction by multiplying it with the speed adjustment factor. In the case of execution of the National road maintenance project in the two-lane two-way urban and interurban road types in the fiscal year of 2015 in Bali province, the loss of time value was at the average of IDR 12,789,000/day/link road. The relationship of traffic volume and loss of time value of the road users was obtained by a logarithm model.

Some geoelectric characteristics of aquifer in parts of Lapai, Central Nigeria were evaluated using Wenner vertical electrical sounding (VES) method. Fifteen (15) VES points were occupied using G41 Geotron Resistivity meter with electrode spacing varying from 10m to 150m while a global positioning system (GPS) tracking device was used to locate the VES points. The 1xD Interprex interpretation software was used for the data interpretation which revealed four layers comprising the top lateritic soil, silty /clayey, weathered basement and fresh basement rocks. The resistivity of these layers varied from 4.54Ωm to 27987.60Ωm while the depth varied from 0.440m to 1079.5m. Longitudinal conductance and transverse resistance calculated from the layers’ thicknesses and resistivities varied from 0.00039Siemens to 2.05Siemens and 3.96×106 Ωm2 to 3.34×107Ωm2 respectively. The aquifer overburden protection capacity in VES 2, 5, 6,9,10 and 11 were relatively low which means the aquifer in these locations are susceptible to contaminants while in VES 15 the protective capacity is higher indicating that the aquifer is protected. Generally, all the locations could be exploited for groundwater at relatively reasonable depths. However, a greater part of the study area has low protective capacity (<1.0Siemens). The consequence of this revelation is that the area is generally unprotected as it allows for infiltration and subsequent contamination of the groundwater and hence good groundwater quality cannot be guaranteed in the area.

Road is the dominant mode of transport in Bangladesh and the road accident rate in Bangladesh is much higher than those of the developed nations. Moreover, the road accident rate has been steadily increasing over the years -- even exceeding the rates in other developing nations. A study based on over 3500 police reported fatalities per year conservatively estimates that the annual economic loss resulting from road accidents is well over US $850 million or approximately two percent of the Gross Domestic Product (GDP). Nearly 50% of the total road accidents occur on National and Regional Highways that have a combined length of 7893 km. The severity of accidents on those roadways is much higher than those of the city and other roadways. However, the government of Bangladesh has been failing to formulate sound policies, and implement targeted programs and projects to improve road safety mainly due to fiscal budget deficits (funding shortage) for a sustained period. The fiscal budget of Bangladesh government has two parts, namely revenue and development. The development budget, a large share of it is dedicated to infrastructure development projects, comes from the government and international development partners (e.g., World Bank, Asian Development Bank etc) sources. There has never been an adequate fund in the national budget to address the road safety issue effectively. Moreover, often road operations improvement and maintenance projects are considered as an indirect investment on road safety. However, without the establishment of a dedicated and sustainable fund, articulation of the visions and development of targeted road safety programs and projects is nearly impossible. This study highlights the road safety issues in Bangladesh and proposes that suitable revenue sources to be used to establish a dedicated fund for the road safety improvement programs and projects. It also recommends that, in conjunction with the dedicated fund, other road safety financing options/tools such as public private partnerships and debt based finance from the expatriate's remittance source need to be considered to improve road safety in general and particularly on national and regional highways. These highways are managed by the Roads and Highways Department, an entity under the road division of the Ministry of Communications.

The objective of this research is to use geophysical methods and spectral analysis techniques for non-invasive characterization of the subsurface in cold regions under isothermal conditions. As a component of the research, this paper provides a critical review of the various geophysical techniques used for characterization with special mention of the application of spectral methods and discussion on the choice of suitable surrogates. Traditional methods of porous media characterization such as pumping tests are invasive and unsuitable for many reasons including the high-cost involved, inability for local scale characterization, and possible contamination problems due to alteration of flow regime. Attempts for non-destructive characterization of subsurface hydraulic properties have resulted in the development of many conceptual and theoretical models. Attributes of the porous media such as porosity, grain size, packing, and geological texture and structure, are known to have direct control on permeability and may be used as surrogates for its estimation. Since complete three-dimensional information of the subsurface is very difficult to obtain, two-dimensional maps of the surrogates aided by heuristic knowledge of the geologic controls on hydraulic properties may be useful for characterization. Most of the non-invasive characterization methods have utilized correlation of such inexpensive, measurable surrogate(s) with permeability in conjunction with one or more geophysical methods (e.g. GPR). Success of such methods depends largely on the choice of suitable surrogate(s) and strength of their correlation with the target property (viz. permeability). Researchers have used spectral analysis techniques to enhance and extrapolate signatures from the images or maps of the surrogates to study possible correlation with permeability for continuous mapping of the permeability.

Investigation to provide information about the location and extent of potential mechanically weak and permeable zones of flood defences is a necessity for effective flood defence management. Geophysical techniques are well suited to detect such zones and are themselves non-destructive. An initial investigation can quickly locate problem areas, and a secondary investigation can provide detailed information about the type and extent of the problem. In emergency situations the results of such investigations would allow the optimum location and planning of emergency repair and strengthening works. The investigative techniques can also be employed in post-flood activities to ascertain the extent of damage inflicted during floods, or as part of a long-term flood defence monitoring programme. JOANNEUM RESEARCH has undertaken work to investigate the potential of various geophysical techniques for application in dike investigations. The geophysical techniques have been tested at pilot sites on actual dikes, which concerning the physical characteristic of the hydraulic situation can be divided into two categories: dikes that constantly withhold water (water on one side and air on the other) and dikes that only withhold water in extreme flood situations (air on both sides). Several geophysical techniques were tested and optimised: infrared, ground penetrating radar, and electromagnetic for initial overview investigations; and 2D or 3D geoelectric surveys to provide detailed information in a secondary survey. The results of the geophysical measurements demonstrate that geophysical methods can be successfully employed to investigate dikes, delivering important information about the homogeneity or inhomogeneity of dikes. Particularly, inhomogeneous areas such as leakages and have been detected and validated

Major road maintenance projects need an accurate cost estimate at the early stage of design. At present, simple and quick models are lacking. Two easy‐to‐use cost models for major asphalt road maintenance projects are developed. The double mean model and the trend line model are based on the cost‐significance method. The historical data used are bills of quantities (BoQs) of major road maintenance projects including reconstruction, overlay and resurfacing. The cost‐significant items in the models are consistent for this type of project. Further BoQs are used to test the accuracy of the cost‐significance models. The two cost‐significance models simplify the data collection and cost modelling process. The double mean model is suitable for quick estimates at scheme design stage, while the trend line model has a much better accuracy and is still simpler than traditional methods, and is therefore appropriate to use for the detailed design stage. Because there are fewer items whose costs require estimating, it is likely that the cost of each item can be estimated more accurately.

Sea defences: Geophysical and NDT investigation techniques

The geological condition of the site in Lagos was investigated using integrated methods. This was necessary following evidence of structural defects prevalent in the area. Against this backdrop, measurements were carried out using in-situ geotechnical and geophysical techniques. The techniques were the Standard Penetration Test, Cone Penetration Test, Electrical Resistivity and seismic refraction surface waves. The various data were collected along eight (8) traverses established strategically in the study area in order to obtain the most desirable results. The results obtained generally show that a low resistive and highly compressive soft soils of organic peats/clays are prevalent in the study area. These geomaterials are characterised with low SPT-N values, low penetrative resistance, low bearing capacities and low electrical resistivity values. The shear (weak) zones have also been identified particularly in the inverted resistivity models. These geomaterials are unfriendly, inimical and severe enough to cause instability in ground conditions. The peat/clay and the weak zones could possibly be responsible for the various degrees of structural defects observed in the study area and should be avoided as foundation placements.