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This study introduces a novel method for evaluating pile–soil interaction based solely on Dilatometer Test (DMT) results, enhancing and extending the established approach originally developed using Menard Pressuremeter Test (PMT) data. Currently, transfer functions utilizing DMT sounding results are in the early stages of development. Presented research fills the gap in DMT-based methods for pile design by introducing transfer functions for reversal loadings to calculate the unit shaft friction of screw displacement piles in Controlled Modulus Columns (CMC) technology. The proposed method utilizes DMT-derived soil parameters, offering a practical and accurate alternative to PMT-based models. Testing research fields were located in the Vistula Marshlands, Northern Poland. Site characterization consisted of piezocone (CPTU) and DMT soundings to characterize the soil profile and estimate soil parameters relevant for pile design. CMCs were installed and statically load tested under various loading schemes. Laboratory direct shear tests on smooth and rough soil-concrete interfaces were performed in both forward and backward directions (reversal loading) to simulate pile loading conditions. Results demonstrate improved adaptability of DMT-based transfer curves to local soil conditions and provide a reliable framework for predicting pile performance in soft soils. Proposed DMT-model returns similar ultimate bearing capacities of the pile to CPT 2012 method for first loading, simultaneously offering better agreement for reversal loading, a situation not accounted for in CPTU 2012 or most other CPT-based methods.

The site characterization of unsaturated soils is well stablished based on laboratory tests, which are expensive and time-consuming. In-situ testing methods, such as the flat dilatometer test (DMT), are an alternative to the traditional approach of drilling, sampling, and laboratory testing. The literature on DMT interpretation is well established on saturated and well-behaved soils. Only few studies deal with DMT interpretation in unusual soils, and little is known about the influence of soil suction on this test. This paper presents and discusses the influence of soil suction on four DMT campaigns carried out in an unsaturated tropical soil site, also incorporating the soil suction influence on the DMT interpretation. Soil suction was estimated by the soil–water characteristic curve (SWCC) and water content profiles. The water content profiles range from 11.3 to 19.7% which corresponds to a suction range estimated by SWCCs mostly between 6 and 200 kPa. Soil suction significantly influenced DMT data up to 5 m depth at the studied site (the unsaturated active zone) increasing the intermediate DMT parameters. The average horizontal stress index ( K D ) was equal to about 1.7 and the average dilatometer modulus ( E D ) was about 4.7 MPa in the active zone and practically doubled their values due to in situ soil suction. The estimated peak friction angle ( ϕ ) was 20–30% higher due to soil suction influence on DMT assuming the soil behaves as a sand like material. Soil suction must be considered to assess the behavior of the investigated soil by the DMT. The suction influence should be incorporated in the effective stress and this approach considerably improved the site characterization of the studied site.

The site investigation is a key part of the design of tunnel construction projects, as it provides accurate geotechnical parameters. A systematic site investigation, which consists of mainly in situ tests and laboratory sample tests, was conducted for the Haimen-Taicang river-crossing tunnel project on Yangtze River. This paper aims to analyze and compare the piezocone penetration testing (CPTU) and dilatometer test (DMT) results of both onshore and under-river subsoils to provide insights into the interpretation of the in-situ tests. The accuracy of well-documented interpretation methods based on CPTU and DMT was discussed. Current empirical correlations between in-situ test results and unit weight, undrained shear strength and constrained modulus of the subsoils were checked, and their site adaptability was discussed in detail. A series of site-specific correlations were derived based on the analysis of the in-situ tests and the comparison between the in situ tests interpretation and the laboratory results. In order to reduce the errors between testing locations caused by soil variability and get the consistent understanding of soil behaviors, CPTU–DMT correlations were reviewed and improved based on local testing results.

An energy pile alters the ground temperature fields around it, which may lead to uneven settlements and a higher risk of failure. The thermomechanical behaviors of soils have been studied extensively in laboratory experiments, while in situ investigations are rare. In this research, flat dilatometer tests (DMTs) are first employed to investigate the thermomechanical behaviors of soil under in situ conditions. The soils were heated by a full-scale precast high-strength concrete (PHC) energy pile, and a series of DMTs were conducted. The results show that temperature changes had a substantial impact on the DMT data of the silt and clay layers. The measured pressures p0 and p1 of the silt and clay layers decreased with increasing ground temperature, and the measured pressure p2 of the silt and clay layers decreased at the beginning and then increased with increasing ground temperature. Although the silt and clay layers have similar variations in the measured pressures, the clay layer has a greater thermal response than the silt layer. Finally, the critical state soil mechanics theory is used to analyze the pore water pressure and thermomechanical properties of in situ overconsolidated soil. The results indicate that the elastic region (yield surface) and mean effective stress of in situ soil decrease with increasing ground temperature, potentially resulting in more irreversible deformation and a higher probability of failure.

Extracting and copper production on a large scale generates large volumes of postflotation mine tailings. The scale of operation and development of tailings storage facilities (TSFs) forces the use of innovative solutions enabling safe storage now and in the future. Any changes to the operation require multi-directional monitoring of the impact of these changes on storage safety. The ongoing exploitation will be ensured by expansion of the TSF and a change in tailings storage technology. This approach will preclude the need for changes to the new location, such as changes of land use, and will minimise the volume of mine waste. The paper presents the results of pilot studies carried out to implement the change in postflotation tailings storage technology at Żelazny Most TSF (Poland) in the future. The aim of the paper was settlements prediction of tailings and comparison of deformations with observed settlements. Settlements prediction of tailings was made on the basis of the results of the DMT (Marchetti Dilatometer Test), recommended for the prediction of natural soil settlement. Depending on the analysed zone of the TSF, settlements ranged from a few centimetres to over 1.5 m. Despite the difference shown, the results of DMT and geodetic measurements indicate a convergent trend of settlement.

The presence of soft soil of river and organic genesis in the basement of road embankments creates problems related to their high deformability. Difficult to assess water permeability, affecting the course of the consolidation and settlement process, requires field studies, such as dilatometer tests. In engineering practice, there are many factors that can affect the basement consolidation process, but they are not simply applied to theoretical models. In many cases, only the observational method allows the selected computational approach to be applied to a specific engineering problem. For this reason, it is one of the approaches strongly emphasized by Eurocode 7. The article presents an example of the application of a temporary load from heavy construction traffic to the consolidation of soft soil under service roads with verification of the subsoil parameters using the dilatometer tests. A horizontal layer of weak soil, loaded with a vertical external load caused by temporary traffic, was assumed for the calculations. For such an arrangement, the classical solution of uniaxial Terzaghi’s consolidation with the water flow in the vertical direction was applied. A computational analysis of the consolidation time and maximum settlement values was performed.

Anguran Lead and Zinc Mine is the largest lead and zinc mine in Iran and the Middle East. In 2006, the north-west wall of this mine had an enormous collapse (approximately 30 million tons). Concerns about another collapse of this wall is more than before with the increasing depth of the ore deposit nowadays. Therefore, the mine development program for excavation the whole of ore deposit, needs to ensure stabilization of the NW wall. In the current research, to estimate weathered depth and probable collapses of the NW wall, the flat dilatometer in situ test (DMT) was used. The flat dilatometer test had the lowest distortions caused by the penetration in the surroundings formations, due to its ground insertion methods without needing borehole drilling. Using this test, it was possible to identify relaxation zones and collapsible zones. Depth of weathered zone was determined 0.5–2 m in the foot of bench and the whole of this weathered zone was distressed by the DMT analyzed data. The whole of landslides were identify surface active and didn’t identify quiescent slip surface in this zone.

•An in-situ test-based calibration approach of a set of the HSSmall model parameters is presented.•A real-world case of deep excavations adjacent to existing tunnels is simulated by the 3D FEM validated with measured data.•Integrate numerical and data-driven modelling to evaluate deformation responses of deep excavations and existing tunnels. This study explores an integrated framework combining in-situ test-based numerical and data-driven modeling to assess the performance of a deep excavation-tunnel system. To achieve the goal, a case history of deep excavations adjacent to existing tunnels in silt/sand-dominated sediments is introduced to establish a base three-dimensional finite element (3D-FE) model. In-situ tests such as cone penetration test (CPT/CPTU) and seismic dilatometer test (DMT/SDMT), as an alternative to laboratory testing, are used to determine a set of advanced constitutive model parameters. The established excavation-tunnel numerical model is then validated against filed monitoring data. A dataset from numerical simulation is created for training and testing four machine learning models (i.e., artificial neural network (ANN), support vector machines (SVM), random forest (RF), and light gradient boosting machine (LightGBM)), which predict the maximum wall deflection, ground surface settlement, horizontal and vertical displacements of the tunnel. Results show that the ANN model outperforms other models in prediction capacity. Its generalization ability in practice is further enhanced by comparing field measurement data and empirical equations. The findings suggest that, with the integrated in-situ tests, FE and ANN modeling could be used to predict deformation responses of deep excavations close to existing tunnels in soft soil. The present study is useful and valuable for practical risk assessment and mitigation decisions.

According to Eurocode 7, limit state design codes generally draw more attention to ultimate limit states than to serviceability limit states. This paper presents the problem of settlement assessment of spread foundations on clays when the foundation design is governed by the serviceability limit state requirements. The paper presents the test results of geotechnical parameters for heavily preconsolidated boulder clays (sandy clay saCl and silty sandy clay sasiCl), which prevail on the Warsaw University of Life Sciences – SGGW campus. The test results were used for settlement calculations of spread foundations. Based on the results of field and laboratory tests, the problem of spatial variability assessment and determination of the characteristic value of soil parameters was addressed. Classical statistics and Bayesian analysis were used in the statistical analysis of the test results. Settlements of spread foundations were calculated based on the soil parameters obtained from cone penetration tests (CPTs) and dilatometer tests (DMTs). Special attention was drawn to the selection of the characteristic values of soil parameters. Determination of the characteristic value of the constrained modulus was performed using two methods: according to the well-known and frequently used formula proposed by Schneider ( ; ) and according to the European draft standard prEN 1997-1:2022-09. Settlement calculations of spread foundations were carried out taking into account changes in the stresses and the constrained modulus in the subsoil. The calculated settlements were verified by field measurements performed during the construction of the object. Comparison of settlements obtained from the characteristic values of the constrained modulus estimated according to prEN 1997-1:2022-09 with the measured settlements indicates that the calculated values were significantly higher than the measured values. Smaller differences between the measured and calculated settlements were obtained when the characteristic values of the constrained modulus were determined from Schneider's formula, while smaller differences were obtained when the mean values of the constrained modulus were used.

Flat dilatometer test (DMT) is a new kind of technology in situ test. This study, through sorting out and analyzing the flat dilatometer test data in subway engineering, obtains the experience of the application of the flat dilatometer test in engineering, and solves practical problems such as soil classification. The results of this study provide an effective basis for the application of flat dilatometer test technology in subway survey and provide sufficient and reliable data for the compilation of regional specifications.