Foundation Soil Research Articles

Dynamic Response of A Group of Cylindrical Storage Tanks with Baffles Considering the Effect of Soil Foundation

Dynamic Response of A Group of Cylindrical Storage Tanks with Baffles Considering the Effect of Soil Foundation

Evaluating soil setup after open metallic pile driving

After driving a pile, foundation soil is restructured and thus regains part of its resistance. This phenomenon is aptly named soil setup. This paper’s focus is to study said phenomenon on eight open metal piles driven in a soil composed of sand and marl, while basing our findings on data of dynamic PDA tests processed with CAPWAP software. Firstly, dynamic tests performed after driving phase and at subsequent re-driving phases show an increase in both the required number of blows for a 10-centimeter drive and in the static resistance to re-driving. The correlations of these resistances with the predictions of the models of Skov & Denver (1988) and Svinkin & Skov (2000) were not satisfactory (R2 of 0.77 and 0.75 respectively). Noting that the setup is mainly due to the increase in friction, a layer-by-layer analysis is carried out by treating the sand and the marl separately. Attained results fit well the Skov & Denver model and align with the experimental results of Murad (2014), but given the model’s limitations in terms of reference time determination, we develop a new function model potency considering immediate setup. The new model fits our attained results very well (R2 of 0.944 for sand and 0.980 for marl). The final static strength after setup is thus calculated as a function of time based on the power function model and conservative estimates. This approach encourages allowing time for the soil to gradually and naturally scar instead of rushing into immediate and costly measures such as patching.

Shadowing effect of an existing tunnel on the evolution of soil arching: impact of tunnel shape

This study evaluates the shadowing effect of existing tunnels on the evolution of soil arching, focusing on the shape of the tunnel (circular and rectangular) through trapdoor experiments. The displacement and shear strain distributions of ground soil resulting from trapdoor movement were estimated using a digital image correlation technique. The results showed that the shadowing effect of the rectangular tunnel was significantly greater than that of the circular tunnel of the same size. The sand above the tunnel was displaced in a double-groove pattern owing to the presence of the tunnel, and the maximum surface settlement occurred between the tunnel boundary and the trapdoor edge. The circular tunnels exhibited consistently higher maximum surface displacements than that in the rectangular tunnels. The shear strain value of soil was lower for the rectangular tunnel case than that for the circular tunnel case. The rectangular tunnels required lesser trapdoor displacement than that of the circular tunnel to obtain the minimum soil arching ratio. The minimum and ultimate soil arching ratios increased as the burial depth ratio increased for both the tunnel shapes. The maximum stress ratio of the tunnel crown was consistently larger for the circular case than for the rectangular case.

Experimental investigation of seismic performance of segmental tunnel with secondary lining under strong earthquake

To assess the seismic performance of large-diameter tunnels in soil ground with and without secondary lining, large scale shaking table tests with geometrical ratio of 1:15 were conducted. The model tunnels were grouped as a tunnel only with segmental linings (Single lining), a tunnel liner with additional semi-ring secondary lining (Semi-ring), and a tunnel with additional full-ring secondary lining (Full-ring). Transverse excitations input from shaking-table were designated as Shanghai artificial accelerogram with magnitudes from 0.3 to 1.0 g. Measurements were made mainly on the time histories of acceleration responses, cross-sectional deformation, extension/closure at longitudinal joints of segmental linings, and earth pressure on external surface, of the model tunnels. Comparison the seismic responses of the tested models gives the effects of secondary lining as: 1) the distribution of acceleration responses on segmental linings is significantly different in the case of single lining model; 2) dynamic normal earth pressure on the external surface of the segmental linings increase along depth, but in different patterns; 3) the constraint effects of semi-ring secondary lining on extension/closure of longitudinal joints are not significant in the upper half of segmental lining. Furthermore, with the increase of earthquake intensity, the constraint effects of full-ring secondary lining on both cross-sectional deformation and extension/closure of longitudinal joints become more remarkable, compared with those of the semi-ring secondary lining.

The Horizontal Bearing Characteristics and Microscopic Soil Deformation Mechanism of Pile-Bucket Composite Foundation in Sand

The pile-bucket composite foundation represents an innovative foundation form that surpasses the horizontal bearing performance of both single bucket-shaped foundations and pile foundations. The intricate interplay between piles and buckets introduces the complexity of the factors influencing the bearing performance of composite foundations under horizontal loads. In this paper, the indoor model tests were conducted to investigate the effects of relative density and pile-to-barrel diameter ratio on the horizontal bearing capacity and surrounding soil pressure of the pile-bucket composite foundation. A sensitivity analysis on the bearing characteristics of the pile-bucket foundation was performed using ABAQUS/CAE 2020 software. The results reveal a consistent variation in load–displacement curves across diverse diameter ratios of piles to buckets. The pile-bucket diameter ratio significantly impacts the horizontal bearing characteristics of the composite foundation. Reducing the pile-bucket diameter ratio improves the horizontal bearing capacity of the composite foundation. When the diameter ratio of piles to buckets diminishes to ≤0.317, the influence of this ratio on bearing performance becomes markedly pronounced. The displacement range of the surface soil decreases with an increase in relative density, while the influence depth of the surrounding soil of the composite foundation significantly decreases as the pile-to-barrel diameter ratio decreases.

Experimental and Numerical Modeling of the Freeze–thaw Response of U-Shaped Channel Lining on Sulfate Saline Soil Foundation

Under the influence of seasonal freeze-thaw cycles, the concrete lining of channels situated on saline soil foundations is highly vulnerable to an array of deleterious phenomena, such as frost heave, salt expansion, and corrosion. To investigate the synergistic interplay among saline soil substrates, U-shaped channel lining structures, and ambient temperatures during freeze-thaw cycles, a novel Hydraulic-Thermal-Salt-Mechanical (HTSM) model is established in this study. The HTSM model elucidates the migration of moisture and salt solute, ice-water phase transitions, and sodium sulfate crystallization within unsaturated saline soils throughout the freeze-thaw cycles. It considers the variations in volume and pore solution volume before and after the phase transition of sodium sulfate. Temperature and salt frost heaving force measurements obtained from outdoor freeze-thaw cycles are compared with numerical simulation results to validate the efficacy of the HTSM model and investigate the distribution patterns of salt frost heaving force (frost swelling force) along the channel. The results showed that the frost swelling force and depth exhibit a great linear relationship and the maximum stress of the U-shaped channel appears at the bottom of the channel, highlighting the good arching force characteristics of the U-shaped structure which prove that bottom of the channel is also the most prone to fracture. Significantly, the initial water content significantly impacts the frost swelling force—it increases by 4% while the frost swelling force increases by 76%. Comparing the numerical simulation results of temperature variations, moisture changes, and salt-frost heaving forces with the outdoor experimental data, it is evident that the proposed HTSM model effectively simulates the salt-frost heaving patterns observed in U-shaped channel linings.

Current trends and biotechnology infused cleaner production of biomaterials for the construction industry: A critical review

Abstract Over the last few decades, there has been a significant awareness established to accept the idea of biotechnology in the field of construction. This growth in awareness has occurred tremendously. In today's world, the development of new building materials and processes that make use of biobased components, such as microorganisms and materials that are mediated by microbes, is an example of developing scientific technology. In general, building materials that are produced through the use of biotechnology, such as cement and grout, are seen as being environmentally benign, affordable, and sustainable. In contrast to traditional cementitious materials, bio-based cementitious materials has the potential to considerably contribute to a large role in reducing the negative impact that the building sector has on the surrounding environment. The purpose of this review work is to present a contemporary evaluation of biotechnology and biobased materials to assess existing developments and suggest new prospective routes for the advancement of construction biotechnology. Based on this study, it was observed that the inclusion of biotechnology can significantly increase the engineering behaviour of cement concrete and weak foundation soil. Hence, its was recommened to implement the idea of biotechnology as effectively in the building industry to obtain the major environmental and economic benefits it offers.

Experimental and Numerical Simulation Study of Water Infiltration Impact on Soil-Pile Interaction in Expansive Soil

A laboratory model of a single pile embedded in Nanyang expansive soil and subjected to water infiltration is applied in this study to examine the interaction between the expansive soil and pile foundation upon water infiltration. The soil matric suction decreases as a result of the rising soil-water content. The amount of soil ground heave reaches its peak of 10.7 mm after 200 hours of water infiltration. As matric suction decreases, pile shaft friction also declines, which causes more of the load at the pile head to be carried by the pile base resulting in more pile settlements. A new numerical simulation method is provided to simulate this issue by coupling the subsurface flow, soil deformation, and hygroscopic swelling to investigate the expansive soil-pile response upon water infiltration. From the numerical simulation model, hygroscopic strain arises as a result of elevated moisture levels resulting from the entry of water, and due to ground heave and the mobilization of lateral soil swelling, the shear stress at the interface between the soil and the pile gradually increases over time. It reaches its maximum value of 4420 Pa at upper depths around 200 hours after the infiltration. The comparison between the lab model testing data and the numerical model results demonstrates a good level of concurrence.

Analytical modeling for the behavior of concrete-cored cement mixing (CCM) pile composite foundation under embankment

The concrete-cored cement mixing (CCM) pile composite foundation is a practical technology for soft soil ground treatment. This paper proposed a theoretical analysis model for the CCM pile composite foundation under embankment in undrained condition which comprehensively considered the interaction between the various components of the CCM pile composite foundation. The working behavior and influencing factors of CCM pile composite foundation under the embankment was also investigated based on the proposed analysis model. The research results showed that: the embankment load was transferred from the outer soil column to the inner soil column. The formation of soil arch effect promoted the concrete core pile to undertake the majority of embankment load, which improved the working behavior of the CCM pile composite foundation under flexible foundation. There was a neutral plane at a certain depth below the ground surface, and the pile shaft above the neutral plane was under negative skin friction, moreover, the vertical stresses of the concrete core pile, cement mixing pile and the soil around the pile all reached the maximum value at the neutral plane.

Configuration of a gravel-rubber geotechnical seismic isolation system from laboratory and field tests

We present the outcomes derived from controlled laboratory experiments on utilizing gravel rubber mixtures (GRM) as a geotechnical seismic isolation (GSI) stratum beneath the foundational structure of the EuroProteas prototype. The study encompassed three distinct GRM compositions characterized by varying rubber proportions relative to the total mixture weight (0%, 10%, and 30%) employed as the foundation soil. These GSI-structure systems were subjected to external harmonic forces applied atop the structure of EuroProteas across a broad spectrum of frequencies and force magnitudes. Preceding the commencement of field experiments, resonant column and cyclic triaxial compression assessments were conducted on specimens featuring identical rubber fractions and mean grain size ratios. Our laboratory tests revealed that an increase in rubber content resulted in a reduction of the shear modulus (Go) and an augmentation of the damping ratio (Do) while concurrently inducing a more linear character in the G/Go-logγ-D profiles. The findings derived from the laboratory examinations align closely with those ascertained from field investigations. Expressly, it was confirmed that a GSI layer with a thickness of 0.50 meters, composed of a GRM incorporating 30% rubber content, exhibited a discernible reduction in the overall stiffness of the GSI-structure system, accompanied by a corresponding alteration in its fundamental vibrational frequency. The enhanced damping within the system manifested through observable reductions in acceleration recordings and diminished strain development at the base of the GRM layer with 30% rubber content, encompassing a wide range of frequencies.

Numerical Investigation of Two Methods to Reduce the Settlement of a Light-Weight Highway Embankment on Soft Soils

The development of road and highway networks sometimes involves passing through compressible soils of poor quality. Given their mechanical properties as foundation soils, these soils are characterized by low short-term shear strength, expressed by undrained cohesion, which increases during soil consolidation, and are also characterized by significant compressibility, resulting in large-scale settlements when a load is applied to them. Nowadays, there are reinforcement methods that make it possible to execute these structures while limiting the risks of instability. This study consists of the numerical analysis of a light-weight embankment of a highway section built on soft soils. Two reinforcement methods are investigated to support the embankment layers and reduce settlement. Interest is given to the behavior of the soils in place before and after the installation of the adopted reinforcement. The analysis is carried out in such a way as to show the importance of the complete consolidation of the soils in place in the long term, which makes it possible to take into account the dissipation of the pore pressures.

Seismic stability evaluation of rubble mound breakwater: Shake table tests and numerical analyses

Rubble mound (RM) breakwaters are coastal structures constructed to provide tranquil condition around the port areas. After past earthquakes such as the 2004 Indian Ocean earthquake and the 2011 Great East Japan earthquake, it was found that stability of breakwater not only depends on the wave action but seismic motions also play an important role for this. Very limited studies are available for the stability evaluation of RM Breakwater under earthquake motions by conducting physical model tests. To the end, an attempt has been made in the study to evaluate the stability of RM breakwater subjected to earthquake loadings. A series of shaking table tests conducted to evaluate the seismic behaviour of the RM breakwater. A prototype RM breakwater is modelled on two layers of seabed foundation soil. Different amplitudes of sinusoidal seismic motions (foreshocks and main shock) are provided at the base of the model. Later, the breakwater stability was evaluated for real earthquake motions. Various parameters such as settlement, horizontal displacement, acceleration-time histories and excess pore water pressure were measured during the tests. Deformation pattern was also studied by photos and videos captured during the tests. During the mainshock, the crown wall settled by 111 % more comparable to second foreshock; and the structure laterally displaced by more than 200 % comparable with first foreshock. The peak acceleration of input wave amplified while it was travelling from bottom to the crest of breakwater. The excess pore water pressure was maximum beneath the rubble mound, in loose sand and it was five times more during the mainshock compared to first foreshock. Due to loss in bearing capacity of foundation soil, the breakwater collapsed. Also, the effects like rolling down of armor units, densification and slumping of core material, shear deformation of breakwater body were observed during the main shock. Thus, the breakwater failed during the mainshock. Numerical analyses were also executed for both sinusoidal and real earthquake motions to make clear the mechanism of the breakwater behaviour subjected to the earthquake loadings.

Vertical seismic response of end-bearing piles in nearly saturated soil

This paper presents a study on the effect of the degree of saturation of the foundation soil on the vertical seismic response of end-bearing piles subjected to P-waves. The research focuses on nearly saturated soil, where the air phase is not continuous and air bubbles are dissolved in the pore water, and thus can be treated as two-phase material. The response of the two-phase soil–pile system is quantified by means of a rigorous coupled hydromechanical model, which is based on Biot’s theory for poroelastic media and treats the air bubbles–pore water mixture as a homogeneous fluid obeying Boyle’s law. Numerical results are used to illustrate the influence of the degree of saturation of the soil layer on the seismic strong motion transferred to the pile head, i.e., the capacity of piles to filter seismic wave energy. This work bridges the gap between single-phase and two-phase saturated soil models, which predict profoundly different pile head displacements at incident wave frequencies of practical interest, and elucidates the mechanisms that lead to these differences.

Building Vibration Measurement and Prediction during Train Operations

Urban societies face the challenge of working and living in environments filled with vibration caused by transportation systems. This paper conducted field measurements to obtain the characteristics of vibration transmission from soil to building foundations and within building floors. Subsequently, a prediction method was developed to anticipate building vibrations by considering the soil and structure interaction. The rigid foundation model was simplified into a foundation–soil system connected via spring damping, and the building model is based on axial wave transmission within the columns and attached floors. Building vibrations were in response to measured input vibration levels at the ground and were validated through field measurements. The influence of different building heights on soil and structure vibration propagation was studied. The results showed that the predicted vibrations match well with the measured vibrations. The proposed prediction model can reasonably predict the building vibration caused by train operations. The closed-form method is an efficient tool for predicting floor vibrations prior to construction.

ESTIMATION DES TASSEMENTS DIFFÉRENTIELS DES SOLS DE FONDATION DE BÂTIMENT : CONTRIBUTION DES SONDAGES DE RÉSISTIVITÉ ÉLECTRIQUE

To estimate differential settlements of building foundation soils, the site on which the structure is based must be geotechnically surveyed in order to determine the deformation parameters and the thickness of the compressible soil layers in various places. This involves conducting destructive surveys. In this study, the use of geophysical methods (electrical soundings) as a substitute for the conventional methods used was considered. The Schlumberger electrodes array was deployed at the level of a control borehole and at three projected footings. The combination of the results of the electrical soundings with the lithological section of the borehole reveals a significant correlation between the variations of cumulative resistivities and the lithological section of the subsoil. The thickness of the compressible layers at the level of the projected footings is estimated to vary between 5 and 6 m. Œdometric differential settlements have an estimated maximum value of 4.56 cm

Thermal consolidation of layered saturated soil under time‐dependent loadings and heating considering interfacial flow contact resistance effect

AbstractDue to the presence of tiny gaps at the interface of two layers of saturated soil, water seepage occurs at a slower rate within these gaps, resulting in laminar flow at the interface. Based on the Hagen‐Poiseuille law, a general imperfect flow contact model was established for layered saturated soil interfaces by introducing the flow contact transfer coefficient Rω and the flow partition coefficient ηω. The investigation focused on the thermal consolidation behavior of layered saturated soil foundations under variable loadings considering the flow contact resistance effect at the interface. By employing the Laplace transform and its inverse transform, a semi‐analytical solution for the thermal consolidation of layered saturated soil foundations was derived. In the context of a two‐layer soil system, the effects of Rω, ηω, and permeability coefficient k on the consolidation process were examined. The obtained results were then compared with three other interfacial contact models, thereby confirming the rationality of the presented model. The study findings revealed that the flow contact resistance effect leads to a clear jump in the pore water pressure. Furthermore, an increase in Rω and a decrease in ηω were found to significantly enhance displacement and pore water pressure, while having minimal impact on the temperature increment. These insights contribute to a more comprehensive understanding of the thermal consolidation behavior of layered saturated soil foundations and underscore the significance of accounting for the flow contact resistance effect in such analyses.

A Binary Medium Constitutive Model for Frozen Solidified Saline Soil in Cold Regions and Its Fractal Characteristics Analysis

In addressing the issue of strength degradation in saline soil foundations under the salt-freeze coupling effects, a binary medium constitutive model suitable for un-solidified and solidified frozen saline soil is proposed considering both bonding and friction effects. To verify the validity of the constitutive model, freezing triaxial tests are carried out under different negative temperatures, confining pressures, and water contents. The pore structure and fractal characteristics of saline soil are analyzed using mercury intrusion porosimetry (MIP) and the fractal dimension D qualitatively and quantitatively, which shed light on the strength enhancement mechanism during the solidification of frozen saline soils. The results show that the constitutive model for frozen solidified saline soil based on binary medium theory aptly captures the stress–strain relationship before and after the solidification of frozen saline soil. The stress–strain relationship of frozen saline soil before and after solidification can be delineated into linear elasticity, elastoplasticity, and strain-hardening or -softening phases. Each of these phases can be coherently interpreted through the binary medium constitutive model. The un-solidified and solidified frozen both show pronounced fractal characteristics in fractal analysis. Notably, the fractal dimension D of the solidified saline soil exhibits a significant increase compared to that of un-solidified ones. In Regions I and III, the values of D for solidified saline soil are lower than those for untreated saline soil, which is attributed to the filling effect of hydration products and un-hydrated solidifying agent particles. In Region II, the fractal dimensions DMII and DNII of the solidified saline soil exhibit a “non-physical state”, which is mainly caused by the formation of a significant number of inkpot-type pores due to the binding of soil particles by hydration products.

Digital modeling of the interaction of a structure with a foundation in the calculation for seismic action

The influence of soil foundtion consideration method on the dynamic characteristics of the building frame has been studied. The object of the study is a monolithic reinforced concrete frame. Modeling of the calculation model according to the scheme "soil foundation - foundation - topside" was performed .Three finite element models have been developed with a variation of taking into account the soil base. Absolutely rigid base, malleable Winkler base and dynamic Savinov foundation are considered. As a result of the dynamic calculation, the frequencies and periods of natural oscillations of the building frame were obtained. Comparison of the obtained results based on three versions of the models has been made. An optimal method for taking into account the soil foundation in the modeling of the soil foundation in the dynamic calculation of the frames of multi-story-buildings is proposed.

Температурный расчет грунтового основания в геотехнических программных комплексах

A crucial step in addressing the challenge of constructing shallow foundations on seasonally freezing heaving soils is performing temperature calculations of the soil foundation. The software packages Frost 3D and QFrost can be used for conducting these temperature calculations. This research compared the results of calculating frost penetration depths of a test site’s soil foundation using Frost 3D and QFrost with data from geotechnical monitoring. The test site was located in Tyumen, in the vicinity of the Bereznyaki settlement. The study found that using Frost 3D and QFrost software packages for modeling the soil foundation allows for determining frost penetration depths with an error of up to 3.5 %, indicating the reliability of the results and the possibility of using these software packages for performing temperature calculations.

Effect of soil-pile contact parameters on pile bearing capacity value

The soil and foundation elements are fundamental to the behavior of a structure. When the foundation soil has a low capacity, it is necessary to transmit the loads to a deeper and more resistant layer, using deep foundations. A pile load test is a field measurement of the bearing capacity (vertical or horizontal) of a foundation element. In addition to a physical model of a load test, the use of computational tools can bring additional understanding. In order to analyze the responses obtained by numerical models compared to field test results, tools that use Finite Element Methods (FEM) and that have a series of constitutive models become a great alternative. This paper aims to study the behavior of Continuous Flight Auger (CFA) piles, aiming to understand the soil-pile interaction regarding the effect of soil-pile contact parameters on pile bearing capacity value. In this way, experimental data from three load tests were compared with numerical simulations using the Mohr-Coulomb constitutive model. Also, a parametric study was completed based on the collected soil data from the literature of the region that most affected the settlement behavior of the load pile. It was concluded that there is a direct and significant influence of the friction coefficient on the pile bearing capacity. In addition, by incorporating more real soil data and parameters representing its actual formation, the results of the pile load test simulation can be taken as an alternative to estimate the ultimate capacity of a vertically loaded pile in the absence of the static load test, which has been widely observed in engineering practice.