Deformation Modulus Research Articles

Innovative Quality Assessment of Pavement Subgrades Using the Glegg Impact Soil Tester

This article presents the case study of our research in the field of innovative methods of pavement subgrade quality control using the CIST (Clegg Impact Soil Tester) device. The CIST device developed by Dr Clegg from the University of Western Australia measures soil compaction indirectly using the CBR value. The value is evaluated based on the deceleration rate of a falling 4.5 kg weight moving in a vertical guide roller. In Europe, for the assessment of the mechanical efficiency (bearing capacity) of cohesive soils in the pavement subgrade, priority is given to indirect assessment methods especially using the laboratory determination of CBR (Californian Bearing Ratio) and directly through the implementation of a static plate load test (SPLT). This article reports the long-term results of our research in the field of verification and validation of an innovative CIST device, which minimizes the time, space, and economic disadvantages of SPLT. This article presents the results of determining the field of applicability of the CIST device for cohesive soils, the correlation dependencies (CD) of the CBR values determined by the CIST device, and, according to STN 72 1016, the CD of the impact dynamic deformation modulus Evd from the CIV (Clegg Impact Value). We consider the most important results of our long-term research to be a recognition of the ability of CIST to assess the quality of cohesive soils up to a compression value of 40 mm, corresponding to a CBR of 2.2% and a modulus of subgrade deformation of 20 MPa. A very strong correlation dependence of CBRClegg [%] on the moisture content of clayey soils in the interval from 5 to 19% was also observed. The presented knowledge led to the creation of relevant documents for the credible implementation of the CIST device in the system approach for assessing the quality of the pavement subgrade.

Empirical evaluation of the strength and deformation characteristics of natural and synthetic gas hydrate-bearing sediments with different ranges of porosity, hydrate saturation, effective stress, and strain rate

Evaluating the mechanical properties of gas (primarily methane) hydrate-bearing sediments is essential for commercial production as a next-generation resource and understanding the global carbon cycle. Triaxial and uniaxial compression tests have been conducted on synthetic gas hydrate and natural core samples recovered from deep-sea beds using pressure coring techniques. The results show that four factors are vital in establishing the strength of hydrate-bearing sediments: hydrate saturation, effective confining stress, porosity, and strain rate. However, no study has evaluated these factors in a unified and quantitative manner, and even if the physical properties of the reservoir are known in detail from logging, predicting the strength has been challenging. In this study, pressure cores were drilled and recovered from the Eastern Nankai Trough in April 2018 after Japan’s second offshore production test, and triaxial or uniaxial compression tests were performed on 12 pressure core samples brought back to the laboratory. The mechanical properties of the hydrate-bearing sediments were classified with previous obtained results from 53 pressure cores and 223 synthetic cores, and empirical equations for triaxial compressive strength and deformation modulus were proposed as functions of gas hydrate saturation, effective confining pressure, porosity, and strain rate. The obtained equations were found to correlate well with the experimental data and can predict the strength and deformation modulus from logging data.

Effect of Fiber Content on Mechanical Properties of Fiber-Reinforced CGF All-Solid-Waste Binder-Solidified Soil.

In order to realize the resource utilization of solid waste and improve the tensile strength and toughness of soil, CCR-GGBS-FA all-solid-waste binder (CGF) composed of general industrial solid waste calcium carbide residue (CCR), ground granulated blast furnace slag (GGBS) and fly ash (FA) was used instead of cement and combined with polypropylene fiber to strengthen the silty soil taken from Dongying City, China. An unconfined compressive strength test (UCS test) and a uniaxial tensile test (UT test) were carried out on 10 groups of samples with five different fiber contents to uncover the effect of fiber content on tensile and compressive properties, and the reinforcement mechanism was studied using a scanning electron microscopy (SEM) test. The test results show that the unconfined compressive strength, the uniaxial tensile strength, the deformation modulus, the tensile modulus, the fracture energy and the residual strength of fiber-reinforced CGF-solidified soil are significantly improved compared with nonfiber-solidified soil. The compressive strength and the tensile strength of polypropylene-fiber-reinforced CGF-solidified soil reach the maximum value when the fiber content is 0.25%, as the unconfined compressive strength and the tensile strength are 3985.7 kPa and 905.9 kPa, respectively, which are 116.60% and 186.16% higher than those of nonfiber-solidified soil, respectively. The macro-micro tests identify that the hydration products generated by CGF improve the compactness through gelling and filling in solidified soil, and the fiber enhances the resistance to deformation by bridging and forming a three-dimensional network structure. The addition of fiber effectively improves the toughness and stiffness of solidified soil and makes the failure mode of CGF-solidified soil transition from typical brittle failure to plastic failure. The research results can provide a theoretical basis for the application of fiber-reinforced CGF-solidified soil in practical engineering.

Experimental study on the significance of pressure relief effect and crack extension law under uniaxial compression of rock-like materials containing drill holes

The drilling pressure relief technology is an effective way to reduce the accumulation of elastic energy in the tunnel envelope, which can reduce the risk of regional ground pressure occurrence. However, there is a lack of theoretical guidance on which drilling parameter has the greatest degree of influence on the effectiveness of pressure relief. The uniaxial compression tests were conducted to study the relationships between drilling parameters (the diameter, depth, and spacing) and the mechanical properties and deformation modulus of specimens. The results show that: (1) The drilling diameter (DDR) and drilling depth (DDH) of single-hole specimens negatively correlate with the peak-failure strength and deformation modulus, while the drilling spacing (DS) of double-hole specimens positively correlates with the peak-failure strength and deformation modulus. It shows that the borehole diameter has a more significant effect on the decompression effect. (2) With the help of the Grey Relational Analysis, the factors affecting the peak-failure strength and deformation modulus of the drilled specimens were ranked in significance. From the largest to the smallest, they are DDR, followed by DDH and DS. (3) The role of the pressure relief mechanism is to transfer the high stress in the shallow part of the roadway to the deep part, reduce the peak strength of destruction and deformation modulus of the peripheral rock in the drilled section, so that the characteristics of the mechanical behavior of the rock are significantly weakened, and the range of the area of the drilled hole decompression is enlarged. During the loading of the borehole, the borehole stress field dominates in the early stage, and cracking starts near the borehole along the direction perpendicular to the direction of maximum principal stress (horizontal direction). In the later stage, the maximum principal stress field dominates and vertical cracks with large widths appear. During crack expansion, the plastic energy dissipation effect is enhanced and the deep impact conduction path is weakened, thus protecting the roadway. This study determined the significance of the pressure relief effect of different drilling parameters, which can guide reasonable modifications of drilling parameters in the field.

Numerical analysis on the factors affecting post-peak characteristics of coal under uniaxial compression

The post-peak characteristics of coal serve as a direct reflection of its failure process and are essential parameters for evaluating brittleness and bursting liability. Understanding the significant factors that influence post-peak characteristics can offer valuable insights for the prevention of coal bursts. In this study, the Synthetic Rock Mass method is employed to establish a numerical model, and the factors affecting coal post-peak characteristics are analyzed from four perspectives: coal matrix mechanical parameters, structural weak surface properties, height-to-width ratio, and loading rate. The research identifies four significant influencing factors: deformation modulus, density of discrete fracture networks, height-to-width ratio, and loading rate. The response and sensitivity of post-peak characteristics to single-factor and multi-factor interactions are assessed. The result suggested that feasible prevention and control measures for coal bursts can be formulated through four approaches: weakening the mechanical properties of coal pillars, increasing the number of structural weak surfaces in coal pillars, reducing the width of coal pillars, and optimizing mining and excavation speed. The efficacy of measures aimed at weakening the mechanical properties of coal is successfully demonstrated through a case study on coal burst prevention using large-diameter borehole drilling.

Wave-absorbing performance of alumina thin-walled hollow particles under freezing condition

The reliability of the absorbing layer is crucial for realizing protective engineering’s protection function. However, the typical wave-absorbing material, sand, is unable to fulfill its intended wave-absorbing function in areas with seasonally frozen soil. This is because the internal pores of the material become filled with ice and the particles freeze. To address this issue, alumina thin-walled hollow particles were chosen as a new wave-absorbing material. These particles can introduce the gas phase into the absorbing layer which is essential for attenuating the stress waves and its wave-absorbing capacity under freezing conditions was investigated by the split Hopkinson bar (SHPB) test. According to the test data, the alumina thin-walled hollow particles are less dense than sand and have a lower wave impedance, allowing them to reflect more incident energy. Moreover, these particles have a better capacity for dissipating the absorbed energy, as compared to sand. Under freezing circumstances, the average transmittance coefficient of alumina thin-walled hollow particles is only 21.95% to 49.30% of ordinary sand. Additionally, the particle size positively correlates with the capacity for wave-absorption. The capacity of alumina thin-walled hollow particles to shatter and release the gas phase under impact stress significantly increases the compressibility of the absorbing layer under freezing conditions, which accounts for their enhanced wave-absorbing effectiveness. The stress-strain curve specifically manifests as a smoother curve and a longer stage of plastic energy dissipation. Other than that, the dynamic deformation modulus of the material and peak stress is lower, while the peak strain is larger. The findings of this study provide a low-cost, high-reliability solution to the problem of frost damage in the absorbing layer in regions with seasonal freezing.

Comprehensive evaluation of strength parameters of soils by using DCP, DSCP, and LWD devices

ABSTRACT Traditionally evaluation of strength parameters of soil using plate load test is time-consuming, laborious and cumbersome process. This study is focused on evaluating the strength parameters of compacted soils, quickly and cost-effectively in terms of dynamic penetration index (DPI), dynamic resistance (DR), cone index (CI), and dynamic deformation modulus (E LWD ), analyzing their relationship with water content. Results, show strength parameters increases as water content decreases,with significant increase in DR, CI and E LWD for CBR changes from 5% to 10%, followed by marginal increase This study emphasized that the strength parameters vary with the physical properties of soils, for which correlations were proposed between CBR, DR, CI, and E LWD values, resulting in best-fit models. These parameters effectively indicate targeted in-situ strength conditions, aiding in assessing repeatability and uniformity of compaction. The mean DR, DPI, N, and E LWD were reported as 61.74 MPa, 6.41 mm/blow, 8 blows/100 mm, and 54.11 MPa, respectively from the field case study.

Toward the use of an intermediate value of the modulus of deformation of soils in geotechnical design

This study presents the results of a critical analysis of the existing methods of selecting the values of ground deformation modulus used in calculating the settlement of designed foundations. The importance of improving the reliability of the determination of the modulus of deformation for ensuring the reliability, economic efficiency and safety of structures is highlighted. It is revealed that the determination of the deformation modulus is not performed at the full depth of soil samples, which can lead to the risk of accidents at facilities. To increase the reliability of deformation modulus determination, a method of interpolation of values based on data from nearby wells is proposed. A new model for determining intermediate values of the deformation modulus is presented, which can be used in calculating the settlement of designed buildings. The results of test problems confirm the high efficiency of the proposed method not only for the calculation of foundation settlement using the values of ground deformation modulus, but also for the control determination of refined values of ground deformation modulus at the stage of geotechnical engineering surveys.

SUBSTANTIATION OF THE ROAD CONSTRUCTION UNBOUND MATERIALS CALCULATION MODEL WITH GEOGRIDS STABILIZATION

Summary. Based on the results of experimental studies conducted on different types of flexible pavement structures, the authors of the article examined the behavior of unbound material reinforced with geogrid. A series of static plate load tests were carried out, and the deformation modulus values of traditional and reinforced pavement structures were determined. The impact of the geogrid, installed at the base of the unbound layer of the pavement structure, on its deformation modulus was investigated. It was found that the use of geogrids significantly increases the equivalent deformation modulus of the pavement, depending on the thickness of the inert material layer and the deformation characteristics of the subgrade soil. The effectiveness of the reinforcement depends on the ratio of the deformation characteristics of the pavement and the subgrade soil, as well as the relative depth of the geogrid installation. The greatest effect is achieved on weak soils under large deformations. The results obtained are significant for further research and practical application of pavement reinforcement technology using geosynthetic materials. Keywords: highway, pavement structure, biaxially oriented geogrid, geosynthetic reinforcement, plate load tests, deformation characteristics, loading, reinforcement coefficient, field experiment

Study on the Damage Characteristics and Internal Variable Modeling of Single-Fracture Sandstone under the Coupling Effect of Freeze–Thaw and Fatigue Load

The fractured rock mass in the western cold region is affected by freezing and thawing disasters and is prone to local damage and fracture along the fissures’ ends. The fatigue damage induced by repeated frost heave and traffic loads seriously endangers the stability of cold region roadbed. This paper selects sandstone as the research object. Firstly, 20 freeze–thaw cycles were performed on fractured sandstone samples with different inclination angles of 30°, 45°, 60°, and 90°. Subsequently, triaxial compression and triaxial fatigue loading tests were conducted to explore the mechanical properties and fracture morphology evolution mechanism during the compression process of freeze–thaw fractured sandstone. Nuclear magnetic resonance technology (NMR) was used to measure the H-containing fluid inside rock pores. The microscopic damage characteristics inside the rock were analyzed from the NMR T2 relaxation spectrum signal and pore size distribution characteristics. Based on the internal variable theory of continuum mechanics, a fatigue model of freeze–thaw fractured sandstone with different inclination angles was established. The results show that sandstone strength was negatively correlated with the fracture dip angle, and the axial deformation and shear failure angle were positively correlated with the fracture dip angle. The mechanical properties of the sandstone were deteriorated by fatigue loading. When the crack angle was 90°, the fatigue failure strength of the rock sample was the lowest. The T2 spectrum distribution of the fractured sandstone mainly had three peaks and the pore size was mainly medium and small pores. There was a small leftward shift after freeze–thaw cycles and fatigue loading. The T2 spectrum area was significantly affected by fatigue loading, with the highest rate of change at a crack angle of 30°. Through the fine correspondence between the axial residual deformation and the deformation modulus, a fatigue model with different crack inclination angles was established using the axial residual deformation as the internal variable, and the rationality of the model was verified by fatigue loading tests.

Mechanical properties of cemented backfill under different unloading rates after cured at different temperatures

In the process of deep filling mining in coal mine, due to the influence of mining and other factors, the confining pressure on both sides of cemented backfill decreases. It is necessary to master the mechanical characteristics of cemented backfill under unloading conditions in different temperature environments to ensure the stability of cemented backfill. To simulate the unloading process of cemented backfill in the deep highland environment of coal mine, triaxial unloading confining pressure tests of cemented coal gangue- fly ash backfill at different unloading rates after curing at different temperatures (20 ℃, 35 ℃ and 50 ℃) were carried out by the Rock Triaxial Testing System, and the mechanical characteristics of cemented backfill unloading were systematically studied. The findings of the study show that, for the same unloading rate, the peak strength of cemented backfill specimen reduces initially before increasing with curing temperature rises. After curing at the same temperature, the peak strength of cemented backfill specimen varies exponentially with an increase in unloading rate. The deformation modulus and volume strain at different unloading rates satisfy an exponential function relationship, while the generalized Poisson's ratio and volume strain satisfy a quadratic function relationship. Under unloading conditions, there was no large fracture or fragmentation of cemented backfill, only cracks appeared on surface. At the same unloading rate, cemented backfill specimen cured at 35 ℃ and 50 ℃ exhibits significantly more shear cracks after failure compared to the material cured at 20 ℃. As the unloading rate increases, the proportion of shear cracks generated during unloading failure of cemented backfill specimen cured at 35 ℃ and 50 ℃ gradually increases. In addition, the theoretical curve of the four-stage cemented backfill unloading constitutive model established in sections is essentially compatible with experimental curve, confirming the theoretical model's reasonableness. The study's findings provide a theoretical basis for evaluating stability of cemented backfill after unloading in deep high temperature (35–50 ℃) environments.

Определение модуля деформации бинарного композита с помощью искусственной нейронной сети

Using of existing methods of determining the characteristics of soils which are part of current regulatory documents and which are based on the hypothesis of normal character of distribution require considerable time and material costs. According to the results of conducted laboratory researches the hypothesis wasn’t confirmed. In the paper it proposes to use trained artificial neural network for determination of the deformation modulus of binary composite «sand — granules of expanded polystyrene». Thus, it has been proven efficiency proposing method using trained artificial neural network in compare classical regression equation for determination of the deformation modulus of the binary composite. With a confidence probability of P = 95 % the absolute value of the relative error is equal to 11,8 % the proposing learning artificial neural network in 11 times less than the absolute value of the relative error of classical regression equation. Also with a confidence probability of P = 95 % the coefficient of determination is equal to 0,5641 and in 6,6 times less than it of regression equation. Further research will be directed to the selection of the values of the parameters of the artificial neural network program for increase the accuracy of determining the deformation modulus of the binary composite.

Experimental study of uniaxial compressive mechanical properties of rough jointed rock masses based on 3D printing

Abstract Roughness and inclination are important factors affecting the strength and deformation properties of jointed rock masses. Serrated joint specimens with varying joint roughness coefficient (JRC) and inclination angle were manufactured by 3D printing technique and cement mortar material. Then, uniaxial compression tests were performed for serrated joint specimens. The results show that when inclination angle equals 0° or 90°, the stress–strain curves of serrated joint specimens with various JRC values are basically the same and display a similar variation trend as that of the complete specimen, hence JRC presents a very little impact. When inclination angle varies from 30° to 60°, the stress–strain curves display a significant difference for various JRC values. Both the compressive strength and peak strain increase with the JRC value. With the increase in JRC value, the stress–strain curve exhibits a stress drop point, and with the further increase in JRC value, the stress drop point obviously delays or disappears directly. Variation in uniaxial compressive strength and deformation modulus with inclination angle is approximately U-shape for serrated joint specimens and displays typical anisotropic characteristics. Due to the variation in inclination angles and JRC values, failure modes of serrated joint specimens under uniaxial compression varies from splitting tensile or shear slip failure to compound tensile and shear failure. Rough serrated joint has a strengthening effect on the resistance ability to vertical load, and large roughness can effectively slow down the shear slip failure of jointed rock masses.

Анализ грейферной выемки волокнистого торфяного сырья

The purpose of the study was to confirm the possibility of implementing the operations of the working cycle of mining equipment with the determination of the range of forces required to introduce the elements of the grab into the deposit and close the jaws in the massif, taking into account the design features of the grab. Research methodology. A series of field studies was carried out using full-scale models of the working bodies of a fork grab in the conditions of a peat deposit to confirm the possibility of implementing the process of extracting raw materials of a low degree of decomposition. Results. It has been established that the average value of the force required overcoming the resistance to the introduction of the grab model: on the site with magellanicum peat – 44.4 kN, with fuscum-peat – 61.5 kN. The average value of the normal stress when immersed in an array of a clamshell equipment element, taking into account the end surface area, is 89 kPa for: magellanicum peat, 123 kPa for fuscum-peat. The average value of the total deformation modulus in the natural occurrence of a peat deposit is 116 kPa for magellanicum peat and 126 kPa for fuscum-peat. The rational distance between the teeth of the jaw model of the fork grab has been determined. With a distance between the teeth of the grab jaw model l=0.25 m, a single drawing body is formed when the captured area of the material is shifted. Conclusion. With the determination of the effort ranges for the implementation of the two main operations of the excavation process, as well as the establishment of the design features of the grab for surface excavation, it was concluded that it is possible to use grab equipment for the surface extraction of fibrous peat raw materials.

Research on the Early-Age Cracking of Concrete Added with Magnesium Oxide under a Temperature Stress Test Machine.

Concrete cracking is a significant issue in the global construction industry, and the restraint stress of concrete is a crucial contributing factor to early concrete cracking. The addition of magnesium oxide additive (MEA) to concrete is a method to enhance its crack resistance. In this paper, concrete specimens with four different contents of MEA were tested with a temperature stress testing machine. The deformation characteristics and mechanical properties of concrete with varying contents of MEA were investigated using both free deformation tests and fully constrained deformation tests. The prediction model for the early restrained stress of concrete was developed by integrating the stress relaxation phenomenon of concrete with models for autogenous shrinkage, temperature deformation, and elastic modulus. According to the results, (1) the thermal expansion coefficient exhibits a pattern of initially increasing and subsequently decreasing with the increasing ratio of MEA; (2) the addition of 3% and 8% MEA can offset 23% and 35.1% of the concrete's self-shrinkage, respectively. Nevertheless, when the added MEA content is 5%, the self-shrinkage of concrete increases by 6%; (3) the addition of 3-8% MEA can result in a 0.5-1.67 times increase in the maximum expansion stress of concrete, as well as a 0.5-0.95 times increase in cracking stress; (4) as the MEA content continues to increase, the stress relaxation level of concrete also increases. In comparison to concrete mixed without MEA, the maximum increase in the stress relaxation level of concrete is 65.5%, thereby enhancing the concrete's anti-cracking ability. However, when the MEA dosage reaches a certain threshold, the stress relaxation enhancement brought about by the addition of MEA will no longer be significant; (5) when compared to the experimental data, the established model of early-age constraint stress accurately predicts the tensile constraint stress of concrete.

Effects of temperature on autogenous deformation and early-age stress evolution in cement pastes with low water to cement ratio

This paper investigates the influence of temperature on autogenous deformation and early-age stress (EAS) evolution in ordinary Portland cement paste using a recently developed Mini Temperature Stress Testing Machine (Mini-TSTM) and Mini Autogenous Deformation Testing Machine (Mini-ADTM). In the Mini-TSTM/ ADTM, CEM I 42.5 N paste with a water-cement ratio of 0.30 was tested under a curing temperature of 10, 15, 20, 25, 30, and 40 °C. X-Ray diffraction (XRD) tests were conducted to measure the amount of ettringite and calcium hydroxide, which reveals the micro-scale mechanisms of autogenous expansion. The applicability of the Maturity Concept (MC) for the prediction of autogenous deformation and relaxation modulus under different temperatures was also examined by the experimental data and the viscoelastic model. This paper leads to the following findings: 1) The autogenous deformation of ordinary Portland cement paste is a four-stage process comprising the initial shrinkage, autogenous expansion, plateau, and autogenous shrinkage; 2) Higher temperature leads to higher early-age cracking (EAC) risk because it accelerates the transitions through the first three stages and causes the autogenous shrinkage stage to start earlier. Moreover, higher temperatures also result in increased rates of autogenous shrinkage and EAS in the autogenous shrinkage stage; 3) Autogenous expansion and plateau are attributed to the crystallization pressure induced by CH. Temperature-dependent CH formation rates determine the duration of the plateau stage; 4) Low-temperature curing can delay but not completely prevent the EAC induced by autogenous deformation; 5) The MC cannot predict the autogenous deformation at different temperatures but can be used to calculate the relaxation modulus, which in turn aids in EAS prediction based on autogenous deformation data.

Strength properties of soils treated with calcium-based flocculants and their impact on vacuum preloading

In this study, a series of unconfined compressive strength tests were conducted to investigate the effect of calcium-based flocculants on the strength and deformation properties of slurry. The test results indicated that the presence of calcium-based flocculants [Ca(OH)2 or CaCl2] significantly enhanced the unconfined compressive strength (qu) of soil. A non-linear relationship was observed between qu and CaCl2 content, revealing that the maximum value of qu is obtained at a CaCl2 concentration of 24.8%. qu exhibited a high increase rate at early curing time in the presence of Ca(OH)2, with a lower increase rate after a longer curing time and high Ca(OH)2 content. The deformation modulus E50 showed an increasing trend with increasing CaCl2 content at 3 and 7 d, followed by a decreasing trend with increasing CaCl2 content at 14 and 28 d. However, the failure strain εf for CaCl2-treated soil ranges from 2.4% to 4.8%, showing no relation with qu. A significant increase in E50 for Ca(OH)2-treated soil in the early curing stages (3 and 7 d) was observed because of the increase in qu. After 14 d of curing, E50 tended to decrease with increasing Ca(OH)2 content. A positive relationship between the degree of vacuum and qu in the presence of calcium-based flocculants was proposed, indicating that a higher qu of treated soil leads to a lower water content after vacuum treatment for the same preloading period, emphasizing that the vacuum treatment efficiency increases with an increase in the qu of calcium-based flocculant-treated soil.

3D conditional random fields simulation for rockfill compaction quality assessment with sparse EVD measurement

The compaction quality of rockfill materials plays a pivotal role in ensuring the stability and durability of runway structures. However, traditional assessment methods relying on limited random sampling may lack representativeness for the entire construction site and overlook potential areas of insufficient compaction. Addressing this challenge, this paper employs the dynamic deformation modulus (EVD), a rapid and nondestructive testing method, to assess the compaction quality of runway rockfill. Subsequently, this paper propose a 3D Conditional Random Field (CRF) model based on EVD to simulate the uncertain spatial distribution of rockfill compaction quality, allowing for the estimation of the overall construction area's compaction quality with a limited number of sample points. The validity of the model is demonstrated through a case study involving a runway expansion project. Additionally, three critical construction factors--namely, measurement points, compaction passes, and compaction materials--are analyzed throughout the construction process. This analysis provides managers with valuable insights and decision-making tools to promptly evaluate the quality of compaction areas, ensuring the stability and durability of the runway.

Оценка несущей способности железобетонной плиты пола цеха на армированном грунтовом основании

A method for calculating the floor structure of an industrial building on a compensatory soil cushion on a base reinforced with vertical elements is considered. The foundation is composed of weak soils and reinforced with driven reinforced concrete piles. The compensation cushion is made of sandy soils compacted to the required deformation modulus. The calculation was performed using the numerical method in the SCAD software package. Information was obtained on the stress-strain state of piles, pad soil and floor slab. The soil of the compensation cushion was tested to meet the strength conditions of A.I. Botkin. The possibility of using a reinforced concrete floor slab of an industrial building has been determined.

Inverse analysis of deformation moduli for high arch dams using the displacement reconstruction technique and multi‐objective optimization

AbstractThe inverse analysis of the deformation moduli of high arch dams based on displacement monitoring data is essential for structural safety assessment. In traditional inverse analysis methods, the deformation moduli are identified based on the single‐objective optimization and the hydrostatic component derived from the statistical model. This type of method has two main shortcomings: First, it treats the essential multi‐objective optimization problem as a single‐objective problem; second, the extracted hydrostatic component may be biased due to the multicollinearity of variables in the statistical model. This paper presents a methodology for the inverse analysis of the deformation moduli of high arch dams under a multi‐objective optimization strategy. The methodology employs empirical mode decomposition to extract the aging component from displacement monitoring data. Then, thermomechanical analysis is used to reconstruct the remaining hydrostatic and temperature components, thereby avoiding the biases encountered in solving the statistical model. The adaptive polynomial chaos expansion method is embedded in the NSGA‐III algorithm to establish and solve multi‐objective functions in the inverse analysis. Additionally, a composite decision index considering errors and test information is proposed to determine acceptable deformation moduli from the Pareto solution set. A high arch dam is selected to illustrate this methodology with static and dynamic monitoring data. The results show that the identified deformation moduli have errors of 3.8% and 7.2% in displacement and acceleration, respectively. The proposed methodology can yield deformation modulus values that are more consistent with the physical implications than those of the single‐objective optimization method.