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Determination of pile bearing capacity is essential in pile foundation design. This study focused on the use of evolutionary algorithms to optimize Deep Learning Neural Network (DLNN) algorithm to predict the bearing capacity of driven pile. For this purpose, a Genetic Algorithm (GA) was developed to select the most significant features in the raw dataset. After that, a GA-DLNN hybrid model was developed to select optimal parameters for the DLNN model, including: network algorithm, activation function for hidden neurons, number of hidden layers, and the number of neurons in each hidden layer. A database containing 472 driven pile static load test reports was used. The dataset was divided into three parts, namely the training set (60%), validation (20%) and testing set (20%) for the construction, validation and testing phases of the proposed model, respectively. Various quality assessment criteria, namely the coefficient of determination (R 2 ), Index of Agreement (IA), mean absolute error (MAE) and root mean squared error (RMSE), were used to evaluate the performance of the machine learning (ML) algorithms. The GA-DLNN hybrid model was shown to exhibit the ability to find the most optimal set of parameters for the prediction process.The results showed that the performance of the hybrid model using only the most critical features gave the highest accuracy, compared with those obtained by the hybrid model using all input variables.

Accurate determination of the axial load capacity of the pile is of utmost importance when designing the pile foundation. However, the methods of determining the axial load capacity of the pile in the field are often costly and time-consuming. Therefore, the purpose of this study is to develop a hybrid machine-learning to predict the axial load capacity of the pile. In particular, two powerful optimization algorithms named Herd Optimization (PSO) and Genetic Algorithm (GA) were used to evolve the Random Forest (RF) model architecture. For the research, the data set including 472 results of pile load tests in Ha Nam province—Vietnam was used to build and test the machine-learning models. The data set was divided into training and testing parts with ratio of 80% and 20%, respectively. Various performance indicators, namely absolute mean error (MAE), mean square root error (RMSE), and coefficient of determination (R 2 ) are used to evaluate the performance of RF models. The results showed that, between the two optimization algorithms, GA gave superior performance compared to PSO in finding the best RF model architecture. In addition, the RF-GA model is also compared with the default RF model, the results show that the RF-GA model gives the best performance, with the balance on training and testing set, meaning avoiding the phenomenon of overfitting. The results of the study suggest a potential direction in the development of machine learning models in engineering in general and geotechnical engineering in particular.

This paper aims to investigate the effect of combined end-and-side grouting on the bearing properties of large-diameter rock-socketed bored piles in highly weathered rock layers. Eight full-scale pile load tests were conducted in the highly weathered rock layer to analyze the enhanced mechanism of the combined grouted bored piles. The test data from pile mechanical testing were compared with the recommended values in the current specification and geological survey report. The results demonstrate significant improvement in the side and end resistances of the combined grouted bored piles, resulting in a substantial increase in the bearing capacity and effective settlement control. It was observed that the construction of impact holes for bored piles can cause severe damage to highly weathered rock structures and weaken the mobilization of side and end resistances. Moreover, it was found that the calculation of the enhancement coefficient in the current specification underestimates the practical bearing capacity. The measured enhancement coefficients for the side and end resistance of piles in fully or highly weathered rock layers range from 2.49 to 3.05 and 2.24 to 2.43, respectively, which are more reasonable and feasible for the calculation. The research findings deepen the understanding of the bearing characteristics of large-diameter rock-socketed bored piles with combined grouting and provide valuable case references for the optimal design of large-diameter combined grouted piles for building foundations in Shenzhen, China.HighlightsPost-grouting had the potential to improve super high-building foundation reliability while reducing pile length and cost.The improvement effect and improvement mechanism of combined grouted bored piles embedded in highly rock strata were revealed.The influence of the size effect for large-diameter piles in highly weathered rock was revealed.The construction of impact holes for bored piles can cause severe damage to highly weathered rock structures and weaken the mobilization of side and end resistances.The enhancement coefficients for the side and end resistance of piles in fully or highly weathered rock layers were proposed.

This paper presents the results from a pile load testing program for a bridge construction project in Louisiana. The testing includes two 54-in. open-ended spun cast concrete cylinder piles, one 30-in. open-ended steel pile and two (30- and 16-in.) square prestressed concrete (PSC) piles driven at two locations with very similar soil conditions. Both cone penetration tests (CPTs) and soil borings/laboratory testing were used to characterize the subsurface soil conditions. All the test piles were instrumented with vibrating wire strain gauges to measure the load distribution along the length of the test piles and measure the skin friction and end-bearing capacity, separately. Dynamic load tests were performed on all test piles at different times after pile installations to quantify the amount of setup with time. Static load tests were also performed on the PSC and open-ended steel piles. Due to expected large pile capacities, the statnamic test method was used on the two open-ended cylinder piles. The pile capacities of these piles were evaluated using various CPT methods (such as Schmertmann, De Ruiter and Beringen, LCPC, Lehane et al. methods). The result showed that all the methods can estimate the skin friction with good accuracy, but not the end-bearing capacity. The normalized cumulative blow counts during pile installation showed that the blow count was always higher for the PSC piles compared to the large-diameter open-ended cylinder pile, regardless of pile size and hammer size. Setup was observed for all the piles, which was mainly attributed to increase in skin frictions. The setup parameters “ A ” were back-calculated for all the test piles and the values were between 0.31 and 0.41.

The excavation method has significant effects on the response of piles, and post-grouting is a great way to improve the response of piles. In this research, field static load tests were performed on three large-diameter and superlong rock-socketed bored piles (LSRBPs) of superhigh-rise constructions. The effects of composite excavation and combined grouting on the response of LSRBPs were studied. The improved effects of combined grouting on LSRBPs that were drilled by composite excavation were discussed. The results indicate that the composite excavation improves construction efficiency but affects shaft-forming quality, thus lowering the bearing capacity of LSRBPs, while combined grouting can contain this defect. Despite reducing the original pile size, combined grouting still significantly improves the bearing capacity of LSRBS and reduces the dispersion of bearing capacity. Existing pile design methods overestimate the bearing capacity of LSRBPs constructed using composite excavation, but underestimate it after combined grouting. The composite excavation forms different pile-rock (soil) interfaces, which affects the effectiveness of combined grouting. The simultaneous application of composite excavation and combined grouting reduces design pile size and improves construction efficiency, thereby achieving the goals of cost reduction and low-carbon construction. The findings have significant implications for the construction and design of LSRBPs.

The effect of exposure to high temperature on rock strength is a topic of interest in many engineering fields. In general, rock strength is known to decrease as temperature increases. The most common test used to evaluate the rock strength is the uniaxial compressive strength test (UCS). It can only be carried out in laboratory and presents some limitations in terms of the number, type and preparation of the samples. Such constrains are more evident in case of rocks from historical monuments affected by a fire, where the availability of samples is limited. There are alternatives for an indirect determination of UCS, such as the point load test (PLT), or non-destructive tests such as the Schmidt’s hammer, that can also be performed in situ. The aims of this research are: (i) measuring the effect of high temperatures and cooling methods on the strength and hardness of a limestone named Pedra de Borriol widely used in several historic buildings on the E of Spain, and (ii) studying the possibility of indirectly obtaining UCS by means of PLT and Leeb hardness tests (LHT), using Equotip type D. Limestone samples were heated to 105 (standard conditions), 200, 300, 400, 500, 600, 700, 800 and 900 ºC and cooled slowly (in air) and quickly (immersed in water). After that, UCS, PLT and LHT tests were performed to evaluate the changes as temperature increases. Results show decreases over 90% in UCS, of between 50 and 70% in PLT index and smaller than 60% in LHT index. Insignificant differences between cooling methods were observed, although slowly cooled samples provide slightly higher values than quickly cooled ones. The results indicate that LHT can be used to indirectly estimate UCS, providing an acceptable prediction. Research on correlating strength parameters in rocks after thermally treated is still scarce. This research novelty provides correlations to predict UCS in historic buildings if affected by a fire, from PLT and non-destructive methods such as LHT whose determination is quicker and easier.

Slow-maintained static load tests were performed on closed-ended and open-ended steel pipe piles driven side by side in a gravelly sand soil profile. The site investigation consisted of multiple cone penetration tests (CPTs) and standard penetration tests (SPTs), as well as laboratory tests on soil samples collected at various depths from the test site to determine basic soil properties. The test piles were densely instrumented with a combination of electrical-resistance and vibrating-wire strain gauges. The open-ended test pile was a specially fabricated double-wall, fully-instrumented pile, allowing for separation of the measurements of the inner and outer shaft resistances. Detailed comparison of the load test results, in terms of driving resistance, load response and profiles of unit shaft and base resistances for the two test piles, is presented and discussed. The applicability of three CPT-based pile design methods is assessed through a layer-by-layer comparison of the estimated resistances with those measured in the static load tests.

The large-scale generation and disposal of fly ash pose significant environmental concerns, highlighting the need for its sustainable reuse in geotechnical applications. This study investigates the performance of fly ash blended with polypropylene fiber as an infill material in geocell-reinforced sand beds to enhance bearing capacity and reduce settlement. Plate load tests were conducted in the laboratory by varying geocell mattress height, cement content, fiber content, and curing period. The results showed that polypropylene fibers improved the shear strength of the fly ash mix. Increasing the geocell mattress height from 0.5B to 1B enhanced the ultimate bearing pressure of a sand bed by 3.4×. At a mattress height of 1B, an improvement factor of 13.18 was achieved at a settlement (s/B) of 12.5%, and this improvement is attributed to confinement provided by the geocell because of enhanced load distribution. Fly ash mix with 6% polypropylene fiber and 5% cement yielded an ultimate bearing pressure of 460 kPa after 3 days of curing, which was 6.9× higher than that of an unreinforced sand bed. These findings demonstrate that fiber-reinforced fly ash is a sustainable and efficient infill material for geocell mattresses, offering both environmental benefits and improved geotechnical performance.

In this paper, joint precast piles with a cross-section of 400 × 400 mm and a pin-joined connection were considered, and their interaction with the soil of Western Kazakhstan has been analyzed. The following methods were used: assessment of the bearing capacity using the static compression load test (SCLT by ASTM) method, interpretation of the field test data, and the dynamic loading test (DLT) method for driving precast concrete joint piles, including Pile Driving Analyzer (PDA by ASTM) and Control and Provisioning of Wireless Access Points (CAPWAP) methods. According to the results, the composite piles tested by the PDA (by ASTM) method differ by 15 percent compared to the static load method, while the difference between the dynamic DLT (by ASTM) method and the static load (by ASTM) method was only 7 percent. So, according to the results, the alternative dynamic method DLT (by ASTM) is very effective and more accurate compared to other existing methods.

The most difficult soil type to work with from a geotechnical engineering viewpoint is a clayey soil layer with high compressibility deposits, which may be encountered in the first layer of the new bridge ramps that can constructed using mechanically stabilized earth walls (MSE). Low shear strength and long-term settling are two primary issues when constructing clayey soil deposits. Utilizing non-reinforcement Franki piles is the best method for enhancing clayey soil deposits. To strengthen soft soil deposits, boost bearing capacity, lessen future settlement, and accelerate construction time. These walls are commonly used in civil engineering projects, especially for highways, bridge abutments, and other infrastructure requiring earth retention. MSE earth walls are more cost-effective, require less labor, and are suited for a variety of site circumstances. Results design data demonstrated that employing in situ concrete casting unreinforced Franki piles for the Ramps (MSE) earth walls in two projects, Al-Zaafaranyah and Doura-Youussifia bridges may enhance the soil layers of MSE, optimizing the load distribution, increased the bearing capacity, minimize the settlement, and accelerate the consolidation time and minimize the construction time. The results of the zone load test showed a significant effect for the tested unreinforced Franki pile with a 0.50 m diameter, which was adequate to design a load equal to 100 tons with reassured behavior, in comparison, the Franki piles type according to the behavior in test results with other types (un-reinforcement concrete bored piles and vibrated stone columns), appeared the superiority of Franki piles comparing with other types in improving results.