GEOMATE Journal

THE GATHERING OF A DATASET FOR TUNNELS AND THE ASSESSMENT OF PREDICTED CONSTRUCTION DELAY MODELS UTILIZING REGRESSION AND ADAPTIVE BOOSTING TECHNIQUES

Tanawoot Kongsung, Nobuharu Isago, Teppei Tomita — Wed, 19 Nov 2025 00:00:00 +0000

Construction delays in tunnel projects have persisted over several decades, often resulting in significant financial and scheduling impacts. Despite extensive efforts, the root causes of these delays and effective predictive modeling approaches remain insufficiently resolved. This study aims to identify the key factors contributing to construction delays and to develop predictive models based on empirical data from tunnel projects in Japan constructed using the New Austrian Tunneling Method (NATM). The dataset includes initial and final displacements, displacement rate, categorical geological classifications, and advance rate (dependent variable), compiled from detailed design and construction records. Descriptive statistical analysis revealed a high frequency of outliers and a non-normal distribution, suggesting underlying heterogeneity in ground conditions. Regression models—both standalone and integrated with K-means clustering—were developed and further refined using Adaptive Boosting (Adaboost) algorithms. Adaboost outperformed other models, achieving higher coefficients of determination (R²) and lower prediction errors. Feature importance and SHAP analysis confirmed final displacement as the most influential predictor of tunneling performance. The principal causes of delay were identified as insufficient geotechnical investigations and unanticipated disaster-related ground instabilities, both of which contributed to design revisions and prolonged construction periods. The study underscores the critical role of comprehensive geological surveys conducted at early project stages and demonstrates the utility of machine learning in enhancing delay prediction. These findings provide actionable insights for improving schedule reliability and risk management in future tunnel infrastructure development.

HEALING EFFICIENCY OF BACILLUS MEGATERIUM FOR MICROCRACKS IN CONCRETE: A STUDY OF BIOPOLYMER ENCAPSULATION PERFORMANCE

Luthfi Muhammad Mauludin, Ambar Susanto, Keryanti, Muhammad Hafizh — Wed, 19 Nov 2025 00:00:00 +0000

Cracks are a primary cause of degradation in concrete structures, typically arising from plastic shrinkage, excessive loading, or environmental exposure. Traditional repair methods, such as epoxy or cement grouting, often involve toxic chemicals and are not economically sustainable. As an alternative, self-healing concrete integrating microbial agents like Bacillus Megaterium offers a sustainable solution for autonomous crack repair. This study explores the encapsulation of bacteria within biopolymer microcapsules using sodium alginate and xanthan gum. The research aims to identify the optimal microcapsule dosage that balances mechanical integrity and healing efficiency. Concrete specimens with 1-5% microcapsule content were tested for compressive strength and crack recovery. Results show that 2% microcapsule addition offers the best balance of strength and healing performance. Analytical tools such as Scanning Electron Microscopy (SEM) and CT scans were employed to observe healing activity and microstructural changes. Self-healing concrete demonstrates high potential for reducing maintenance needs, enhancing structural longevity, and contributing to environmentally sustainable construction practices.

MODIFIED – MSRS ANALYSIS OF AYALA BRIDGE DUE TO SPATIAL VARIATION OF GROUND MOTION (SVGM)

John Paul R. Tumangan, Gilford B. Estores — Wed, 19 Nov 2025 00:00:00 +0000

Extended structures, such as bridges, experience variations in ground motion, which cause multiple excitations in the supports. Spatial variation in ground motion is primarily influenced by factors such as incoherence, wave passage effects, and local site conditions. Philippine Highway Bridges are designed using the DPWH–BSDS 2013, in which the seismic excitations are uniform across bridge supports, neglecting the spatial variability of motion. In this research, the concern for the difference in ground motion experience between supports was addressed, considering a Multiple Support Excitation for the Ayala Bridge. The dynamic analysis was performed in ANSYS, which allows varying ground motion conditions. For the Uniform Support Excitation, the DPWH–BSDS 2013 was used for generating the Response Spectrum and used Single–Point Response Spectrum analysis. On the other hand, a Multi–Point Response Spectrum analysis was used to account for the effects of MSE through a modified response spectrum generated in MATLAB, which accounts for SVGM. A significant impact on the bridge’s seismic performance was observed, as indicated by the p-values related to displacement and shear responses of 0.0012 to 0.0037 and 0.0000 to 0.0268, respectively, across all piers; and in moment response with 0.0012 to 0.0237 for piers 2 to 6. The seismic performance of the bridge is significantly affected by the type of excitation experienced by the bridge supports. Therefore, considering MSE when designing highway bridges is necessary because it can affect the overall bridge performance.

HARDENING PROPERTIES OF GRANULATED BLAST FURNACE SLAG ACTIVATED BY FINE SLAG POWDERS FROM DIFFERENT SOURCES

Tomoyuki Hirano, Hiroyuki Hara — Wed, 19 Nov 2025 00:00:00 +0000

Granulated blast furnace slag (GBFS), when activated by an alkaline stimulant, GBFS releases chemical components and forms hydrates such as calcium silicate hydrate (C-S-H), leading to strength development and imparting cohesive properties despite its granular nature. However, because GBFS hardens slowly and its cohesive properties also varies, making it difficult to predict, this behavior is not reflected in Japanese design standards. To incorporate its cohesive properties into geotechnical design, a better understanding of its hardening behavior is required. Approaches to accelerate GBFS hardening is not only the addition of cement but also the addition of blast furnace slag powder (BFS-P) as an alkaline stimulant. However, the effectiveness of BFS-P varies depending on its production source. This study examined the hardening properties of GBFS mixed with three types of BFS-P sourced from different steel plants. Two moisture conditions—unsaturated and saturated—were considered to simulate applications in land and port structures. The results revealed that the MnO, Fe₂O₃, and TiO₂ contents in BFS-P significantly influenced GBFS hardening. A strong correlation was observed between compressive strength and hydrate content measured by thermogravimetric (TG) analysis at 30–600°C. Furthermore, the degree of saturation had a notable effect on strength development. Specifically, the hydrate content required for strength development was 0.283% and 0.376% in the unsaturated and saturated conditions. Unsaturated conditions, hydrates formed bridges between GBFS particles via the meniscus, which also increased the density of the hydrates themselves, resulting in higher strength despite lower levels of hydration reaction.

CHLORIDE DIFFUSION RATE IN LOADED FLY ASH CONCRETE USING STEADY-STATE MIGRATION TEST

Sri Murti Adiyastuti, Kemal Pramayuda, Eko Charnius Ilman — Wed, 19 Nov 2025 00:00:00 +0000

Chloride-induced corrosion is a major durability concern for concrete structures in marine environments, particularly under mechanical loading, as the resulting micro-cracking and cracking can accelerate chloride ingress, allowing these corrosive ions to reach the steel reinforcement more easily and compromise the structure's integrity. This study investigates the combined effect of mechanical pre-loading and fly ash replacement (0%, 20%, 30%, and 40%) on chloride diffusion in high-strength concrete. Sixteen concrete discs were tested using the NT Build 355 steady-state migration method for durations of 7 and 14 days. Before testing, a load of up to 2,000 kilograms was applied to eight specimens, while the remaining eight were left unloaded. The chloride diffusion coefficient was calculated using the Nernst-Planck equation. The results demonstrated that increasing fly ash content consistently reduced chloride ingress, with a maximum reduction of 79.8% observed in specimens with 40% fly ash under pre-loading conditions. These reductions were repeatable across both durations and fly ash percentages, with notably greater performance observed at 30% and 40% replacement compared to 20%. Replacing cement with 30–40% fly ash significantly enhances the durability and extends the service life of concrete structures in marine environments, even when subjected to pre-loading. Additionally, this approach contributes to sustainability by reducing cement consumption, which in turn lowers carbon dioxide emissions.

COMPARATIVE STUDY OF CONCRETE COMPRESSIVE STRENGTH USING POTABLE AND RIVER WATER WITH MULTIPLE LINEAR REGRESSION PREDICTION

Rugin Morfe, Christ John Marcos, Jan Kenn Dulatre, Samwell Cacapit — Wed, 19 Nov 2025 00:00:00 +0000

Concrete strength development depends significantly on water quality, yet in many regions, reliance on potable water (PW) in construction is both unsustainable and costly. This study assesses the viability of river water (RW) as a substitute in concrete mixing and presents a predictive model utilizing Multiple Linear Regression (MLR). Testing was conducted on 36 concrete samples with 3 different mix ratios (1:2:4, 1:1.5:3, and 1:1:2) and water–cement ratios of 0.55, 0.60, and 0.65. The findings indicated that RW attained compressive strength with the 1:2:4 mix at W/C 0.55, satisfying the 15 MPa specification for structural concrete. A two-sample t-test (p = 0.1147) indicated no statistically significant difference between RW and PW specimens, confirming RW’s potential as an alternative mixing water. The MLR model, developed exclusively from Cavite RW data, demonstrated strong performance (R² = 0.877, RMSE = 1.57 MPa) and identified cement content and water–cement ratio as dominant strength predictors. While its predictive power is limited to the tested RW source, the framework demonstrates transferability to other contexts through recalibration. This study is novel in bridging empirical RW testing with statistical prediction, offering both sustainability insights and a decision-support tool for concrete mix design.

MECHANICAL PROPERTIES OF CONCRETE WITH TYPE F FLY ASH ADDITION UNDER ACIDIC CONDITIONS

Mardewi Jamal, Indra Ariani, Muhammad Andryan, Erniati Bachtiar, Masdiana — Wed, 19 Nov 2025 00:00:00 +0000

Concrete is a fundamental construction material whose performance can be significantly improved through the incorporation of supplementary cementitious materials such as fly ash, a by-product of coal combustion. This study examines the effects of replacing 20% of cement with Type F fly ash on the mechanical properties of concrete exposed to acidic mine water over varying curing periods (28, 42, 56, and 86 days). A total of 33 cylindrical specimens (150 mm in diameter and 300 mm in height) were prepared and immersed in acidic mine water to simulate aggressive environmental conditions. The results showed that concrete with 20% fly ash reached a compressive strength of 24.67 MPa at 28 days, then increased to 26.37 MPa at 42 days, and subsequently declined at later ages. In contrast, the split tensile strength consistently increased, peaking at 2.89 MPa at 56 days. The incorporation of Type F fly ash was proven to improve the mechanical resistance of concrete under acidic exposure by reducing the detrimental effects of acid attack. These findings indicate that fly ash-modified concrete exhibits superior mechanical performance and acid resistance, with the optimal curing period observed at 42 days.

RELIABILITY-BASED EVALUATION OF FINE GRAIN EFFECTS ON LIQUEFACTION RESISTANCE

Sumiyati Gunawan, Vienti Hadsari — Wed, 19 Nov 2025 00:00:00 +0000

Liquefaction evaluation can use deterministic or probabilistic methods. The deterministic approach is limited by its inability to address uncertainty from soil complexity and heterogeneity, as well as the probabilistic nature of earthquakes. This method is often inadequate for accurate liquefaction analysis, as it does not reflect true field conditions. Conversely, probabilistic analysis allows for uncertainty and establishes a safety factor proportional to the associated risk. This research analyzes at how the influence of fine particles affects the likelihood of liquefaction, using the Lind-Hasofer reliability theory. This theory estimates the any probability of reliability (Ro) by converting the nonlinear limit state function into a linear form around the design point. The reliability of liquefaction (Ro) is determined using factors such as earthquake magnitude (Mw), maximum shaking strength (a_max/g), total pressure (σ_v), effective pressure (σ'_v), percentage of fine particles (FC), and SPT blow count (N_SPT). Results from 16 drilling locations with different amounts of fine particles and earthquake loads show that cyclic resistance increases with (N₁)_60CS, but decreases when fines content exceeds 35% or when (N₁)_60CS< 13. The empirical relationship between SF and Ro (y = 8.898x^3.0536, R2 > 0.9267) highlights that some layers with SF ≥ 1 still correspond to low Ro < 0.8, indicating the limitations of deterministic analysis. Overall, the probabilistic approach provides a more realistic and risk-consistent assessment of liquefaction potential, making it more suitable for risk- and performance-based geotechnical design.

ECONOMIC LOSS ANALYSIS DUE TO THE FAILURE OF PAMUKKULU DAM IN TAKALAR, SOUTH SULAWESI, INDONESIA

Wed, 19 Nov 2025 00:00:00 +0000

Every dam has the potential to fail due to disasters like earthquakes or other unforeseen events. Dam failures caused by extreme weather are particularly difficult to predict, which can lead to casualties and significant economic losses. This study aims to analyze the potential economic losses resulting from the failure of the Pamukkulu Dam, located in Takalar Regency, South Sulawesi Province, Indonesia. Extreme weather is considered the primary factor causing failure, projecting the worst-case scenario. The Probable Maximum Precipitation (PMP), the maximum rainfall that can occur in an area, was calculated using the Hershfield method, while the inflow discharge analyzed was the Probable Maximum Flood (PMF). The Synthetic Unit Hydrograph (SUH) was selected using the Creager method, resulting in ITB-1b being chosen. Dam failure and flood inundation simulations were conducted using HEC-RAS 6.6 software, based on two failure scenarios: overtopping and piping. The overtopping scenario produced the highest peak discharge, reaching 33,247.67 m³/s, which was used to calculate economic losses for the most extreme condition. The simulation results showed that the inundated area due to dam failure under the overtopping scenario reached 110.79 km². Economic loss analysis was performed using the ECLAC method, based on the inundation area, land cover types, flood depth, combined with unit replacement values and damage factors. The estimated economic loss from the Pamukkulu Dam failure under the overtopping scenario is approximately IDR 1.12 trillion. The findings of this study are expected to support post-disaster recovery efforts and serve as a reference for developing flood risk management strategies.

INTEGRATING FIELD DATA AND NUMERICAL MODELING TO ASSESS MICROPLASTIC DISTRIBUTION IN THE AQUATIC ENVIRONMENT OF HA LONG BAY, VIETNAM

Hung Son Pham, Huu Huan Nguyen, Xuan Hai Nguyen, Dinh Kha Dang, Thi Thuy Pham — Wed, 19 Nov 2025 00:00:00 +0000

This study aimed to investigate the microplastic distribution in the aquatic environment and sediments, and integrate field data and numerical modeling to simulate the spreading of microplastics to gain valuable insights into microplastic accumulation and infiltration into the sea. The study showed that the microplastic density in seawater was ranging from 0.01 to 0.69 particles/m3; the color of microplastics were white/transparent with 41.3%, blue 22.3% and yellow/orange 21.3%; the morphology of microplastics were thin, spherical and fibrous filaments, accounted for 96.9%, of which the size from 1-5mm accounted for 87.9%; the main types of microplastics were HDPE and PS accounting for 47.4% and 18.8%, respectively. The amount of microplastics found in the sedimentation was rather low, up to 12 particles/kilogram, was mostly found in the coast and in rivers. The spreading of microplastic modeling indicated that the high microplastic concentration areas were primarily located in the coastal regions of Ha Long and Cam Pha cities; and the microplastic generated from the inland did not affect Ha Long Bay due to the geomorphological structure with numerous islands that limited the dispersion of microplastics into the offshore. The zones with the highest microplastic concentrations coincide with areas of intensive human activity, including cruise tourism, coastal services, maritime transport, coal mining, and coastal industrial zones. Hence, the waste capture in estuaries and coastal areas and the limitation of single-use plastic products on cruise ships are needed to avoid microplastic movement to the sea.

PRESERVATION STRATEGIES OF PAVEMENT BASED ON ROUGHNESS INDEX AND LIFE CYCLE COST

Muh Bahrul Ulum Al Karimi, Anno Mahfuda, Andi Muflih Marsuq Muthaher — Wed, 19 Nov 2025 00:00:00 +0000

The design life, traffic volume, regional conditions, quality specifications, and other factors are all taken into consideration by the pavement design standards implemented in several nations. The design eventually leads to the pavement's ability to serve as access to designated locations. For various reasons, the relationship between planning and operation often falls apart. However, the lack of comprehensive preparation for preservation and rehabilitation throughout road service life is one notable cause. After designating and forecasting the periods and expenses required during the pavement's service life, this study aims to offer an alternative perspective on planning. Both rigid and flexible pavements in new condition with a 40-year design life are the pavements that will be observed. In this instance, the International Roughness Index (IRI) will be used to estimate the pavement's functional bearing capacity. Preservation strategy is chosen to extend the service life of pavement to be 50^th years. The Life Cycle Cost Analysis (LCCA) approach and the IRI value will be combined to create forecasts of the costs and schedule that will be incurred throughout the road's service life. The LCCA will utilize agency cost and user cost values. Compared to rigid pavements, agency costs are higher when flexible pavements are reconstructed. Rigid pavements are typically more costly than flexible pavements when considering other factors, including user cost. According to the research, rigid pavements are more effective for long-term pavement construction. Furthermore, this study would help stakeholders make decisions on road pavements.

FLEXURAL BEHAVIOR OF REINFORCED CONCRETE BEAMS RETROFITTED WITH ULTRA HIGH PERFORMANCE CONCRETE USING LOCAL MATERIALS

Mardiana Oesman, Syifa Nadia Iskandar, Muhamad Irfan Nurdin — Wed, 19 Nov 2025 00:00:00 +0000

The performance of reinforced concrete (RC) elements often declines over time due to material deterioration, environmental exposure, or changing functional requirements, leading to reduced safety and serviceability. This study investigates the flexural behavior of RC beams retrofitted with Ultra-High-Performance Concrete (UHPC) overlays developed entirely from locally available Indonesian materials, without the use of nanomaterials, making it more practical and sustainable for developing regions. RC beams with a compressive strength of 30 MPa were retrofitted with UHPC layers of 15, 30, 50, and 70 mm thickness, while a 50 mm normal concrete layer served as a control. Experimental testing included load–deflection monitoring, stress–strain measurement, crack pattern observation, and failure mode assessment. Findings revealed that a 30 mm UHPC overlay achieved the highest load-carrying capacity, while 50 mm provided an optimal balance of stiffness, ductility, and toughness. In contrast, 70 mm caused over-reinforcement and brittle failure, and 15 mm offered minimal enhancement. These results demonstrate that UHPC produced from local resources offers an effective, durable, and sustainable retrofitting approach for RC beams in resource-limited settings.

INVESTIGATION ON THE DURABILITY OF CONCRETE WITH RICE HULL ASH (RHA) USING SORPTIVITY AND RAPID CHLORIDE MIGRATION TESTS

Wed, 19 Nov 2025 00:00:00 +0000

Rice hull ash (RHA) is an agricultural residue that typically exhibits pozzolanic properties. In this study, RHA was used as a partial cement replacement in concrete. Physical and chemical characterization tests using X-ray Fluorescence (XRF) and X-ray Diffraction (XRD) revealed that the RHA is an amorphous material with over 90% SiO₂. Concrete specimens with 5% and 10% RHA percentage replacement by weight were prepared. After 28 and 56 days of curing, the water sorptivity, and chloride migration were evaluated. Results showed that for the sorptivity tests, all specimens containing RHA exhibited lower sorptivity values after 28 and 56 days of curing relative to the control. The rapid chloride migration test showed that the concrete specimens with RHA consistently outperformed the standard concrete, further indicating that the addition of RHA increased the durability of concrete. From the results, RHA can be used as a viable partial cement replacement up to 10 wt%, with a marked improvement in durability properties. The use of RHA as partial cement replacement can result in a more environmentally friendly concrete.

COMPARISON OF FILTRATION LOSS REDUCTION IN HORIZONTAL DIRECTIONAL DRILLING MUD USING RICE STRAW WITH INDUSTRIAL ADDITIVES

Bantita Terakulsatit, Sakchai Glumglomjit — Wed, 19 Nov 2025 00:00:00 +0000

Frac-out is a prevalent challenge in Horizontal Directional Drilling (HDD), arising when drilling fluid pressure exceeds the mechanical strength of surrounding geological strata. This induces fractures, allowing fluid to escape into subsurface formations or reach the surface, thereby compromising operational efficiency and threatening nearby ecosystems. Addressing this issue, the present study explores rice straw—a cellulose- and silica-rich agricultural byproduct—as a natural additive in HDD fluids. Its performance was compared with conventional industrial additives, including Carboxymethyl Cellulose (CMC) and Lost Circulation Materials (LCM), under controlled conditions at room temperature and pressures of 20, 50, and 100 psi. Key parameters examined included fluid viscosity, filtration loss, and mud cake formation. CMC, at 0.7% concentration, exhibited optimal rheological properties with the highest viscosity and lowest filtration loss across all pressures. Rice straw at 7% concentration showed promising results in enhancing mud cake thickness and minimizing fluid loss, particularly at low pressure, though its structural stability diminished at higher pressures. LCM maintained consistent mud cake formation but had limited impact on viscosity and fluid retention. Morphological analysis via SEM revealed that composite formulations containing mixed additives improved microstructural density and filtration uniformity. These findings highlight rice straw’s viability as a cost-effective and eco-friendly alternative to synthetic additives, especially for use in moderate pressure drilling and environmentally sensitive conditions.

2D ANALYSES OF GLOBAL STABILITY OF A GEOSYNTHETIC-REINFORCED MECHANICALLY STABILIZED EARTH RETAINING WALL WITH DIFFERENT SOIL CONDITIONS

Van Hung Pham, Dinh Phuc Hoang — Wed, 19 Nov 2025 00:00:00 +0000

The technology of reinforcing slopes with geosynthetics retaining walls has been widely applied in highways, infrastructure, hydraulics, seaports and civil works. The stability of geosynthetic-reinforced retaining walls is the major interest. The limit equilibrium method (LEM) is regularly known as the primary method for stability analysis of unreinforced and reinforced slopes due to its economy, effectiveness and simplicity. The paper presents several limit-equilibrium methods for slope stability analysis. A case study is taken from the section from Km0+360 to Km0+440, which belongs to the Huong Son-Kep town highway project, with an embankment height of 9 meters. The soil foundation profile consists of an organic soil layer with a thickness of 0.3 to 0.5 m, followed by a layer of clayey soil in semi-hard to hard state. The soil parameters are taken from the in situ and laboratory tests. The stability of a 9-height geosynthetic MSE wall is analyzed by employing various LEMs embedded in Geostudio software version 2018 R2. The paper then evaluates the influence of different soil conditions, including the internal friction angle, cohesion, unit weight and surcharge on the stability of the wall. The numerical outcomes indicate that the Janbu method gives a factor of safety that is 8% smaller than that of Bishop, Spencer and Sarma. The Bishop method is then suggested for the following studies. Additionally, the results indicate that the parameters of the foundation soil truly impact the stability of the geosynthetic-reinforced retaining wall structure.

THE CORRELATION BETWEEN STATIC PILE CAPACITY AND DYNAMIC PILE CAPACITY IN DIFFERENT SITES IN BASRA CITY, CASE STUDY

Jaffar A. Kadim, Ihsan Al-abboodi, Osamah Salim Al-Salih, Oday A. Abdulrazzaq — Wed, 19 Nov 2025 00:00:00 +0000

The present research concerns the correlation between the static pile test and the dynamic pile test of driven piles in Basra city by using two types of pile, which are the precast reinforced concrete piles and steel tube closed-end piles. 100 pile tests in the Majnoon oil field, which is located in the north of Basra City, Southern Iraq, are considered in this paper, which focuses on the ultimate pile capacity as the criterion in establishing the correlation between the two test types. The CAPWAP program was used in determining the dynamic pile capacity, while Davisson's method was applied as a criterion in estimating the ultimate pile capacity. The Results have shown that a very strong correlation between the two types of pile tests and the dynamic pile tests, which gave higher values of the pile capacity than the static pile capacity and the case method. Also, the results indicate that the damping factor of soils in dynamic tests showed some variation larger than the quake value from the values of the case method.

ANALYSIS OF GAS RATIO DRILLING TO IDENTIFY THE G-80 SANDSTONE RESERVOIR FOR WELL CORRELATION IN THE SEMBERAH FIELD, KUTAI BASIN

Desianto Payung Battu, Adi Tonggiroh, Meutia Farida — Wed, 19 Nov 2025 00:00:00 +0000

Data uncertainty caused by drilling activities can affect the accuracy of distinguishing productive from non-productive zones, especially in fluid characterization and reservoir evaluation, which are core objectives of geoscience. Each well in Semberah has an objective to penetrate several layers of target, including both oil and gas reservoirs. Gas ratio analysis is an established method for identifying reservoir characteristics by analyzing formation fluid molecules that rise to the surface with the drilling mud when the drill bit breaks through the formation. The integration of drilling data, well logs, and gas analysis from six wells in Semberah has led to a deeper understanding of reservoir potential during drilling. The analysis focused on G-80 sandstone, one of the reservoirs found throughout the Semberah field. Similar trends were observed in total gas compared to resistivity log values, which ranged from 42 to 700 units, versus resistivity measurements from 6.0 to 18.7 ohms. The C1/Sum C ratio ranged from 0.8 to 0.9, WH value indicated dry gas, BH value more 50 is gas while below 50 is water or undeveloped reservoir. The fluid mobility characteristic of the estimated potential porosity gas ratio indicates an approach to porosity values derived from petrophysical analysis. The results of this study demonstrate that gas ratio analysis can support geoscience research and contribute to a broader understanding of the area.

ESTABLISHING A TRAFFIC IMPACT ASSESSMENT MODEL FOR LARGE-SCALE URBAN CONSTRUCTION PROJECTS IN VIETNAM

Do Van Manh, Vu Anh Tuan, Nguyen Kim Hoang, Dinh Tuan Hai — Wed, 19 Nov 2025 00:00:00 +0000

The accelerated pace of urbanization in Vietnam has led to growing concerns about traffic congestion, especially in areas undergoing large-scale construction. This paper presents a structured and practical framework for conducting Traffic Impact Assessments (TIA) tailored to major urban construction projects. By leveraging both macroscopic and microscopic simulation tools VISUM and VISSIM we provide a robust methodology to forecast, assess, and mitigate traffic impacts from proposed developments. The framework centers on critical peak hours (7- 8 AM and 5- 6 PM) to capture the most severe traffic conditions. Data inputs include socio-economic indicators, base-year traffic volumes, and spatial configurations from major Vietnamese cities like Hanoi. The simulation results highlight the stark contrast in Level of Service (LOS), delay times, and queue lengths across three scenarios: existing conditions, post-development without mitigation, and post-development with interventions. Our findings emphasize the necessity of early-stage traffic modeling in urban planning and advocate for the institutionalization of simulation-based TIA in Vietnamese regulatory practice. This study offers urban planners, policymakers, and traffic engineers a replicable model for integrating transportation considerations into the design and approval process of large-scale developments.

EFFECT OF DIFFERENT CRUMB RUBBER SIZES ON IMPROVEMENT OF BUTON ROCK ASPHALT MODIFIED

Wed, 19 Nov 2025 00:00:00 +0000

Buton Rock Asphalt contains 20–30% asphalt, and the rest is granular material, so its use is limited due to low penetration value. Mineral granules must be included as aggregates. This study optimizes Buton Rock Asphalt with Waste Engine Oil as a softener and Crumb Rubber from tire waste. Study of Crumb Rubber sizes consists of Large (0.297–0.149 mm), Medium (0.148–0.0075 mm), and Small (<0.0075 mm), each sequentially added to the Buton Rock Asphalt modified. Tests included asphalt physical properties, volumetrics, Marshall properties, viscosity, and modeling using Response Surface Methodology. Crumb Rubber contains the most significant elements of Carbon, 67.57% and oxygen, 21.75%, with small amounts of silicon, potassium, calcium, and copper. The optimum value of Crumb Rubber content based on size is known to be 8% for CR-Large, 5% for CR-Medium, and 1.75% for CR-Small. The lower the Viscosity on Temperature Sensitivity value, the more stable the viscosity to temperature changes, with the following values: CRS (–3.997, CRL (–3.523), and CRM (–3.151). The CRS size type showed the highest Residual Stability Index, meaning it has the resistance to temperature and water changes. Multivariate Polynomial Regression analysis results showed that the addition of CR to BRAM significantly affected the volumetric asphalt concrete mixture. All regression models exhibited a high fit, with R² values ranging from 0.95 to 0.98 (p < 0.0001). This study is limited to short-term laboratory tests; the performance of Petroleum Asphalt with the involvement of 30% Rock Asphalt still needs further study.

GEOPHYSICAL AND GEOTECHNICAL STUDY FOR ASSESSING THE POTENTIAL OF LANDSLIDE DISASTERS: A CASE STUDY IN KRUENG SABET, ACEH JAYA, INDONESIA

Muhammad Syukri, Zul Fadhli, Purwandy Hasibuan, Haris Saputra, Rini Safitri — Wed, 19 Nov 2025 00:00:00 +0000

This study investigates landslide susceptibility in the Krueng Sabet Lamno region of Aceh Jaya by integrating geophysical and geotechnical methods, addressing a key gap where these approaches are often applied in isolation. The central hypothesis is that correlating resistivity, seismic refraction, and Cone Penetration Test (CPT) data can more accurately identify weak zones prone to slope failure than single-discipline analyses. Field investigations along the Jantho–Lamno road revealed Silty Sand and Fine Sand layers as potential slip-prone horizons, with CPT data highlighting low-resistance zones and high pore-water vulnerability. Seismic refraction delineated shallow layers, while resistivity models detected low-resistivity anomalies corresponding to water-saturated sediments. From these datasets, three principal subsurface layers were interpreted: Sand and Clay, Weathered Bedrock, and Limestone Boulder. It is emphasized that these interpretations represent subsurface models rather than direct geological confirmation from surface outcrops. Results demonstrate that Silty Sand layers, although overlain by seemingly stable Fine Sands, are critically susceptible under heavy rainfall, groundwater rise, or additional load. The novelty of this study lies in its integrated approach, providing a holistic characterization of slope instability that strengthens disaster mitigation strategies and offers a replicable methodological framework for other landslide-prone regions.