Data Assimilation (DA) algorithms has been successfully employed in geotechnical problems to jointly estimate the state of the system and model parameters, however, the impact of the field monitoring ...setup on the performance of DA is often overlooked. In this paper, the impact of the field monitoring setup on the performance of DA is studied. The Ensemble Kalman Filter is used as the DA algorithm as part of a synthetic experiment which includes a fully coupled hydromechanical numerical model of an embankment constructed on soft ground. The results of the assimilated parameters show different rate of convergence toward their synthetic true value which corroborates well with the results of the global sensitivity analysis performed in this study. In order to investigate the difference in influence between the quantity and type of measurement, different monitoring strategies were chosen in this study. The results indicate that the effective friction angle and Poisson's ratio are better estimated when the horizontal displacement is included along with the vertical displacement in the observation space of the DA procedure. Finally, the strong correlation between observation type and parameter convergence is independent of the type of initial prior knowledge, but strongly depends on the measurement location.
The Sumedang-Cirebon Km 68+750 road section is a national road and an important transportation infrastructure in West Java. Albeit the road section's slope has previously been strengthened with bored ...pile reinforcement, the slope continues to move. This study's objective is to examine slope stability by considering earthquake loads and to suggest improvements for efficient slope reinforcement. Slope stability analysis utilizing PLAXIS 2D program based on the finite element method and DMT-KD Method which is the result of field testing using the Flat Dilatometer Test (DMT)). PLAXIS modeling results show that the slope failure line is deeper below the bored pile reinforcement. The results of the analysis using DMT-KD method showed similar slope failure, the conclusion is DMT-KD method can be the initial basis for slope stability analysis on mudstone. The PLAXIS modeling results obtained a static safety factor of 1.113 and a safety factor due to an earthquake of <1, both of which fall short of the requirements of minimum of 1.5 for static loads and 1.4 for earthquake loads. The body of the road develops cracked as a result of this issue. Additional reinforcement modeling is carried out using bored piles and gabions. As shown in the results of additional reinforcement modeling, bored pile reinforcement that reaches below the slope failure line is more successful than gabion reinforcement at the slope's base in raising the safety factor.
Over the past few years, the weight of goods that are transported on roads in Egypt has rapidly increased. Engineers have developed safe methods for building roads on soft soils as a result of a ...growing need for improvement. But Highway pavement design on soft clay soil is still a very difficult problem to solve. It frequently results in issues like unstable roadbeds or excessive settlement. As a result, treating soft soil roadbeds has gained importance. To support the appropriate pavement portion and its traffic loads, this study intends to improve the clay soil using various techniques. In this study, quicklime is used to stabilize soft clay soil. geogrid layers are also used to strengthen the base and subbase layers which increases the overall strength of the pavement section to sustain heavy loads above. A finite element program (PLAXIS 2D) was used to simulate these improvement techniques to identify the best solutions for the problem. Results showed that improving a 60 cm layer of subgrade soil with quicklime combined with adding a geogrid layer in the middle of the subbase layer gives the best results.
Metode pembebanan awal (preloading) dan drainase vertikal adalah salah satu metode yang digunakan untuk meningkatkan kekuatan geser tanah lunak. Pembebanan awal dilakukan dengan tujuan ...mengkonsolidasi lapisan tanah lunak dengan besar pembebanan yang sama atau lebih daripada beban yang akan dipikul oleh tanah baik saat maupun setelah konstruksi. Sedangkan drainase vertikal dapat mempercepat proses konsolidasi. Perkembangan drainase vertikal adalah penggunaan PVD (Prefebricate Vertical Drain). PVD dipasang untuk mengalirkan air yang terdisipasi akibat proses konsolidasi. Analisis ini bertujuan untuk membandingkan besar penurunan yang terjadi pada proyek reklamasi peti kemas Belawan fase II dengan pemodelan pada Plaxis 2D dan 3D dengan dan tanpa memperhitungkan efek smear zone. Dari hasil analisis diperoleh besar penurunan yang terjadi pada proses konsolidasi dengan pemodelan Plaxis 2D dengan dan tanpa memperhitungkan efek smear zone adalah 2,288 meter dan 1,922 meter sedangkan dengan pemodelan Plaxis 3D diperoleh besar penurunan 2,077 meter untuk analisis tanpa memperhitungkan efek smear zone dan 1,930 meter untuk analisis dengan memperhitungkan efek smear zone.
This study used a finite element analysis approach employing Plaxis 3D to analyze the stress concentration ratio, a critical parameter in geotechnical engineering, to examine stresses operating on ...stone columns and soft soils. This study also looked at the effect of the stiffness ratio between the stone column and the neighboring soil. With the same length and three different diameters, 0.8 m, 1.0 m, and 1.2 m, or three area replacement ratios ranging from 7% to 16%, respectively, floating and end-bearing stone columns were used. The influence of soft soil undrained cohesion, cu ranging from 6 kPa to 40 kPa, was also considered in the current study. The stiffness ratio for columns to adjacent soil, end bearing or floating stone column, and area ratio all have a significant impression on the performance of the stone column in treating soft soil and stress transmission mechanisms in the enhanced soil body, according to parametric studies. The average stress concentration ratio in soil improved with an end-bearing stone column of φ= 35° and raised to 2.63 and 4.71 at φ = 50°, ranging from 1.41 to 2.35 for area replacement ratios of 7% and 16%.
In Vietnam, landslides frequently occur on cut slopes along the road system during the rainy season. An understanding of the contributing factors and triggering mechanisms is essential so that ...effective measures can be taken to stabilize cut slopes and mitigate impacts caused by landslides. This study uses as a research subject the largest deep-seated landslide triggered by heavy rainfall on July 21, 2018, and the subsequent sliding induced by 5-day continuous rainfall events on the Halong–Vandon expressway. We examined the causative factors, failure mechanisms, and characteristics of the landslides through detailed geological investigation, unmanned aerial vehicle (UAV) surveys, and analysis of data from geology, geomorphology, well-prepared documents of rainfall events, and the expressway project. Results show that the heavy rainfall was the triggering factor for both events while slope cutting was the main landslide causative factor. The slump-type landslides occurred on weathered limestone layers that were parallel to the dip-slope direction of the strata. Geological settings of highly fractured and weathered sandstone, siltstone, and limestone combined with the development of karst caves favored the buildup of groundwater levels in deep layers, thereby causing deep-seated landslides. The analysis shows that in addition to geological factors, the landslide occurrences resulted from anthropogenic effects including the improper design of the calculation method for safety factors in road construction and quarrying activities. Site evidence and UAV photos also reveal that the July 21 landslide body on the lower slope was reactivated to travel downward due to the dynamic effect of the subsequent sliding on July 31. Based on numerical analysis using the Plaxis 2D model, an estimated sliding surface similar to the actual plane was simulated for the entire slope. Furthermore, the study presents an appropriate solution that has been applied to slope stabilization.
The issue of soft soil settlement has been a significant concern for several decades, prompting researchers to explore various approaches to enhance soft soil conditions and mitigate excessive soil ...settlement. Commonly employed techniques in this field include stone columns, encased stone columns, and foundation level adjustment. In the present study, a parametric investigation was conducted to assess the effectiveness of these different techniques in reducing expected excessive settlement for reinforced concrete cylindrical tanks located on Port-Said weak soil. A 3D finite element model was developed using PLAXIS 2D/3D to simulate a completely symmetric cylindrical tank. The numerical model replicates the typical construction and operation stages of the tank, employing Mohr-Coulomb and Hardening constitutive models to represent the layered soil in the analysis. The findings of this study aim to provide valuable design guidelines for constructing circular storage tanks in the Port-Said district, addressing the specific challenges posed by soft soil settlement.
In the paper, there are examples of complex geotechnical problems in both 2D and 3D that are modelled using PLAXIS software on the specialist workstation provided by the Czech Geotechnical Society to ...their members.
