Bearing Capacity Ratio Research Articles

Kinematic bearing capacity analysis of strip footings on reinforced soils using discretisation technique

The kinematic discretisation technique of upper bound limit analysis is adopted in this study to evaluate the limit load of a strip footing located on the soils reinforced with different geosynthetic layers. The reinforcement is assumed to withstand the tension but not bending moment. The failure model of the reinforced foundation soil is generated using the discretisation method, a ‘point by point’ technique. Two failure modes of the reinforcement, the tensile rupture and sliding, are considered in the analysis. This article proposed the formulas for the first time to evaluate the effect of soil friction angle φ on the ultimate bearing capacity and on the failure mechanism of foundation. The calculation results are given considering different reinforcement layers, which describe the impact of different reinforcement depth and length on the ultimate bearing capacity. The optimum positions of different reinforcement layers and the optimum reinforcement length are obtained. The bearing capacity ratios are also presented in figures combing impact of reinforcement depths, soil cohesion and friction angle. The present method was verified by the results reported in literature. The present method can provide a reference for the footing design on the reinforced soils.

Identifying the effect of subgrade layer thickness of soil stabilized with waste foundry sand and fly ash on bearing capacity

The issue of subgrade soil often involves unstable soil properties, such as low bearing capacity, susceptibility to expansion and shrinkage, and vulnerability to erosion and deformation due to traffic loads and weather conditions. Unstable subgrade soil can cause various infrastructure problems, including cracks, settlement, and damage to road surfaces. Therefore, stabilizing subgrade soil is an important step to ensure the reliability and longevity of highways. One effective and sustainable method for subgrade soil stabilization is by utilizing local waste materials. The use of local waste materials such as fly ash (FA) and waste foundry sand (WFS) not only improves the physical and mechanical properties of the soil but also helps reduce environmental impact by repurposing pollutants. This study aims to analyze the effect of the thickness of subgrade layers stabilized with FA and WFS on bearing capacity. The initial stage includes examining the physical and mechanical properties of natural soil and soil stabilized with FA and WFS. The waste content used is 9 % FA and 15 % WFS by dry weight of the soil. Subgrade modeling was conducted using a steel box measuring 60×60×60 cm with a soil thickness of 30 cm. Load testing was carried out on 5 layer variants that had undergone 4 days of curing. The study results found that the ultimate bearing capacity (qult) of 890 kPa was produced by the V4 layer, which is a subgrade with a 30 cm thick layer of soil stabilized with FA and WFS at a settlement of 6 mm. The bearing capacity ratio of 2.87 means that the subgrade with a 30 cm thick layer of soil stabilized with FA and WFS experienced an improvement in bearing capacity of 2.87 times that of the subgrade with untreated soil material. The results obtained can be applied in practice to the local geotechnical conditions of the project site in West Java, including natural soil properties and seasonal changes

An Investigation into the Variables Influencing the Structural Bamboo Architecture Using Filled Concrete and Cement Mortar

Bamboo, as a green building material, plays a vital role in construction. Bamboo has good properties and appearance, making it highly attractive for building structures and designs. Since the compressive capacity of bamboo is considerably lower than its tensile capacity, with the ratio typically ranging between 300% to 900%, this limits its application dimensions in construction. Therefore, filling the original bamboo structural members with specific materials or applying different connection methods can not only maintain the appearance of the bamboo structure but also improve its compressive capacity and overall durability, thus expanding the application range of bamboo structural members and enhancing the performance of the architectural design process. Two hollow bamboo specimens were among the eight BFC specimens tested for this paper. Key components such as transverse stiffeners, steel bars, filler materials, and bamboo nodes were examined for their influence on the specimens’ ductility, peak strain, ultimate bearing capacity, and failure mechanisms. The test results showed that the ratio of the ultimate bearing capacity of BFC specimens to hollow bamboo samples could reach up to 538%, while the peak strain differences were minimal. A non-linear finite element model was developed and its accuracy confirmed based on the test results. This work proposes a new approach to determine the final axial compressive capacity of BFC columns by creating an elastic model of transversely isotropic cylinders. As a result, the primary goal of this study is to establish a foundation for more scientific building design techniques and procedures by examining the axial compression mechanics of structural bamboo filled with cement and concrete (BFC) and how it influences building design.

Geogrid reinforcement for improving bearing capacity and stability of square foundations

Abstract Shallow foundations are often the most economical option for building support, as they distribute structural weight to soil layers, require minimal earthwork, and do not necessitate specialized machinery. The most common type of soil in the city of Karbala is sandy soil. It is granular and loose by nature which has a relatively low bearing capacity. According to previous studies, the soil weakness is one of the problems with shallow foundation construction. Thus, the aim of this study is to improve the properties of the soil using geogrid reinforcement. Three critical parameters are examined, including depth, size, and number of geogrid layers in the soil reinforcement process to increase bearing capacity and decrease soil settling. The effect of geogrid depth (u) was studied by considering four depth ratios (u/B = 0.5, 1.0, 1.5, and 2.0) in order to determine the ideal depth of the geogrid layer, where (B) refers to the width of the footings. The results indicated that a decrease in depth ratio significantly increased the bearing capacity of footings built on reinforced soil layers compared to those built on natural soil, and the settlement reduction ratio (SRR) also increased. The size of the geogrid layer (i.e., width of the geogrid layer (b) was evaluated by evaluating four size ratios (b/B = 1.5, 3.0, 4.5, and 6.0). With an increasing size ratio of the geogrid layer, the bearing capacity ratio (BRC) was significantly improved. Additionally, the study examined the optimal number of geogrid layers, focusing on single and multiple layers with N = 1, 2, 3, and 4. The results showed a higher BRC for footings on reinforced soil layers, as well as a significant rise in SRR with an increase in the number of geogrid layers. Finally, it was concluded that the optimal depth ratio was u/B = 0.5, the size ratio was b/B = 4.5, and reinforced with three geogrid layers, which provided the highest bearing capacity and SRR. The experimental test results were verified by comparing them with those calculated using theoretically developed models. The variation between the experimental and theoretical results is reasonable, confirming that the experimental testing results exhibit a high degree of accuracy.

Physical model study on failure mechanism of strip footing on reinforced granular deposit

This study proposes guidelines for predicting the failure mechanism of a shallow strip footing resting on geosynthetic-reinforced granular deposit at different stages of footing settlement. Physical model tests are performed on footings resting on unreinforced and geosynthetic-reinforced soil. The reinforcement parameters varied include the depth between consecutive reinforcements, number of layers and the depth of the reinforced zone. Additionally, contours of deformation and maximum shear strain of soil and mobilised tensile strain in reinforcement with increasing footing settlement are studied. The improvement of bearing capacity ratio and the peak tensile strain in the reinforcement was monitored for three normalised settlement ratios of 5% (low), 10% (medium) and 25% (high). The reinforced soil models were found to depict primarily a punching shear failure limited solely within the reinforced zone at s/B of 5%. This was supplemented with a well-formed triangular wedge in the underlying unreinforced soil at s/B of 10%. In addition to above mechanisms, the radial shear zones were prominent at s/B of 25%. Failure mechanisms have been proposed eventually for each s/B value investigated, including guidelines on the upper and lower bounds of the load dispersion angle in the reinforced soil and wedge angle of the underlying unreinforced soil.

Bearing capacity of perforated surface foundations on sand

ABSTRACT Perforated foundations find widespread use in supporting offshore structures. However, there is a limited exploration of the bearing capacity of both single and multiple perforated foundations under combined loading. The finite element method is used to calculate the effect of perforations on the bearing capacity of strip surface foundations on sand subjected to combined loading in this study. The normalized bearing capacity ratio and yield surface are used to present the variation of bearing capacity, and the variation is explained by the relevant failure mechanism. The outcome indicates that the critical perforation ratio is around 0.07, and the value depends on the perforation number and loading conditions. When the perforation ratio is less than the critical perforation ratio, the combined bearing capacity of the perforated foundation will not be reduced. The bearing capacity decreases with the perforation ratio, where the number and ratio of perforation determine the decline rate and the shapes of the yield surface.

Performance evaluation of recycled concrete aggregates with geosynthetics as an alternative subbase course material in pavement construction

This study investigates the feasibility of using recycled concrete aggregates (RCA) as subbase materials in roads through laboratory experiments. Various physical tests were conducted on the soil subgrade and RCA subbase, followed by cyclic plate load tests to assess the impact of geosynthetic reinforcement on the bearing capacity of RCA materials. The ultimate bearing capacities of different RCA configurations ranged from 186 to 480 kPa, similar to previous studies on natural and recycled aggregates. The geocell-reinforced section exhibited excellent performance, with a measured ultimate bearing capacity of 480 kPa. The Geocell-Geogrid and Geocell-Geotextile sections showed the highest bearing capacity ratios at 2.58 each, indicating superior performance. Reinforced RCA infills demonstrated improved settlement values under repeated loading, with the geocell-geogrid section effectively reducing permanent settlement. The study concludes that RCA can be a substitute for natural aggregates in road subbase materials, mitigating the environmental impact of construction and demolition waste.

Use of steel slag to improve the mechanical properties of subgrades in clayey soils

Large quantities of steel slag are generated annually throughout the world. Some slag from steel manufacturing is reused in the generation of other materials, such as hot mix asphalt aggregate, pipe filling, concrete, among others. The research aims to enrich the mechanical characteristics of soils and minimize road construction costs. The objective of this research is to find a material that increases the mechanical properties of the subgrade in clay soils with different plasticity indices using Electric Arc Furnace Slag (EAF) in percentages: 5%, 15% and 25% of the weight of the soil. From the tests carried out on the soil samples using parameters, it was possible to classify them by the Unified Soil Classification System (USCS) and also by the American Association of Highway Transportation (AASHTO) as low and high clays. plasticity. When testing the samples in their natural state and the samples with EAF, results were obtained that showed an improvement in the physical and mechanical properties of the clay soils with the addition of EAF, increasing the values of the Bearing Capacity Ratio (CBR) and the maximum dry density. of the clay soil as the percentage of HAE in the mixture increased. The optimal HAE addition content corresponds to 25% of the weight of the soil.

Lubrication Modeling of the Reciprocating Piston with High Lateral Load and Various Conditions in a Swash Plate-Type Piston Pump

Most asymmetrical lateral forces occur in the reciprocating piston mechanism, which is widely applied as a major component of power equipment. When this lateral force greatly acts on the piston, it comes into contact with the cylinder. To prevent this negative phenomenon, lubrication characteristic evaluation and control technology are necessary. In this study, a boundary lubrication model considering the elastic deformation of the contact surface was adopted to perform a lubrication analysis of a piston hydraulic pump widely used in the aviation and plant industries. The piston/cylinder mechanism was analyzed in terms of contact force, characteristic thickness, and power loss while varying various design and operating parameters (friction coefficient, clearance, profiling shape, operating speed, and pressure). In the overall bearing capacity to withstand the tilt of the piston, the bearing capacity ratio due to contact at the interface increased more steeply than the bearing capacity ratio in the fluid lubrication area. Profiling of the piston head played a positive role in reducing power loss but also increased piston tilt. This trend appeared more clearly as the head profiling degree of processing Increased. Lastly, the effects of variable operating speed and pressure were examined. High operating speed caused low contact force, and high operating pressure caused high contact force. Through this study, it was possible to predict the lubrication performance and power loss of reciprocating piston pumps used in the field more realistically through appropriate boundary lubrication modeling.

Experimental Study on Seismic Performance of Prefabricated Columns Connected Using a Novel Dry Sleeve

Prefabricated structures are widely used because of their advantages of energy savings, environmental protection, standardization, and universality. However, due to the complex structure of the joints, it is easy to make the joint installation difficult and the prefabricated column connection unreliable, and further lead to the poor seismic performance of the structure. Therefore, a new type of dry sleeve joint with double screw sleeve without support is proposed, and the seismic performance and influencing factors of the new dry-sleeve-joint prefabricated column are studied. This study encompasses seven reinforced concrete columns characterized by cross-sectional dimensions of 600 mm × 600 mm. Among these, five specimens feature a novel dry sleeve connection, while the remaining two specimens were entirely cast-in-place. Low-cycle reversed loading experiments were conducted on all specimens to analyze and compare the damage patterns, hysteresis curves, skeleton curves, displacement ductility, energy dissipation capacity, and ultimate bearing capacity between precast and cast-in-place columns. Several parameters, including fabrication method, axial compression ratio, longitudinal reinforcement diameter, and hoop spacing, were examined. The findings demonstrated that the calculated-to-tested ratio of the ultimate bearing capacity for the prefabricated specimens was determined to be 0.62, indicating a high level of safety. The displacement ductility coefficient for each specimen ranged from 2.43 to 3.31, while the ultimate drift ratio was within the range of 1/41 to 1/33, satisfying the specified requirements for seismic performance. However, the hysteresis curve of the prefabricated specimens exhibited a pinching effect, which may be related to the existence of a weak layer on the joint surface of the post-cast section. In general, the shape of the new dry sleeve is maintained in the test, the connection form can effectively transfer the force, and the longitudinal bars can be strained and yield when the prefabricated column reaches the peak load. The new type of dry sleeve connection can be used for longitudinal reinforcement connection of reinforced concrete columns with seismic design.

Laboratory Model Test on The Sand Column for Reinforcement System of Flexible Pavement

Flexible pavement failures in Indonesia are primarily attributed to weak subgrade conditions, necessitating soil reinforcement measures. This study aimed to enhance soil-bearing capacity through soil reinforcement experiments utilizing a mixture of sand columns, rice husk ash, and cement. A prototype was constructed, including a 1×1×1 m steel box, an IWF steel frame, a dial gauge, a steel plate, and a proving ring, to apply a load to soil arranged within the iron box using a 3-ton hydraulic jack. The study focused on a clay soil type (following the AASHTO method) and conducted soil reinforcement in four scenarios. The result shows that in all scenarios involving a sand column, Scenario 1: 3% sand, 3% rice husk ash, and 6% cement obtained a qult is 0.23 kg/cm2 and BCR 114.94%; Scenario 2: 3% sand, 6% rice husk ash, and 3% cement obtained a qult is 0.12 kg/cm2 and BCR 11.49%; Scenario 3: 6% sand, 3% rice husk ash, and 3% cement obtained a qult is 0.14 kg/cm2 and BCR 26.44%; Scenario 4: 6% sand, 6% rice husk ash, and 0% cement obtained a qult is 0.24 kg/cm2 and a BCR of 116.09%. Notably, scenario 4, featuring a column composition of 6% sand, 6% rice husk ash, and 0% cement, achieved a significant increase in bearing capacity (qult) with a value of 0.24 kg/cm2 and a high Bearing Capacity Ratio (BCR) of 116.09%. Scenario 1 was the most effective in reducing moisture content by 4% relative to the original soil moisture content, with a mixture comprising 3% sand column, 3% rice husk ash, and 6% cement. The findings suggest that applying soil columns can enhance the performance of flexible pavements.

Development and optimization of a novel response‐amplified friction damper with different friction pairs

AbstractIn order to improve the efficiency of friction dampers, a shear‐type response‐amplified friction damper (RAFD) was proposed, which utilized a lever mechanism to amplify the shear displacement and increase the sliding distance of friction pairs. Cyclic loading tests were conducted on 12 RAFD specimens to evaluate the effects of machining processes, friction materials, loading protocols, and bolt pretension on the mechanical performance of the specimens. The results showed that the RAFD specimens with NAO and brass friction pads exhibited plump hysteresis loops, and the bearing capacity, effective stiffness, energy dissipation, and equivalent viscous damping ratio all met the stability requirements of FEMA 356 for the friction damper. Reducing the clearance between pins and holes and strengthening the hole edges shortened the plateau near zero resistances of the hysteresis loops by 75%–90%. Furthermore, combined with rotational analysis of the lever, a design methodology for the RAFD specimen was developed. Based on the response amplification factor R, key mechanical indices such as bearing capacity and equivalent friction coefficient were derived, and a theoretical hysteresis model for the RAFD was constructed, which matched well with experimental results.

THE MODEL ANALYSIS OF REINFORCED BAMBOO WOVEN FOR SHALLOW FOUNDATION SUPPORTING BEARING CAPACITY ON SOFT SOIL

North Jakarta generally has soft soil characteristics. Construction built on soft soil is a big problem due to the low bearing capacity of the soil and the large settlement. Therefore, a reinforcement is needed with the aim of increasing the carrying capacity of the soil. In this study using woven bamboo reinforcement, the use of this reinforcement can be an alternative to increase the bearing capacity of the soil used as the basis for shallow foundations. Variations in depth and number of layers of reinforcement are used to obtain the maximum value of the soil bearing capacity. The depth variation used is 0.25B and 0.5B with a variation of 2 (two) layers of reinforcement. The research method used is on a laboratory scale. The data obtained were then analyzed by comparing the value of the bearing capacity of the soil without reinforcement using reinforcement which was expressed by Bearing Capacity Ratio (BCR). The results showed that the largest bearing capacity value occurred in the modeling distance of 0.25B with 2 layers of reinforcement of 459.064 kN/m2 while the smallest value of bearing capacity occurred in modeling of the distance of 0.5B with 1 layer of reinforcement of 321.227 kN/m2 and increased carrying capacity land with an increase value of 76.31 %.

Experimental study of the behavior of square footing on reinforced sand with treated geotextile

Bearing capacity of reinforced footing clearly depends on the characteristics of interface between geosynthetic and soil. A suitable solution for increasing the bearing capacity is to treat the geotextile surface by various additives. This study reported the results of plate load test on square model footing resting on reinforced sand with and without treated geotextiles to survey the effects of the treatment of geotextile on settlement and bearing capacity. The treated geotextiles were made using additives onto the surface, with a layer of sand located on the top. Geotextile sides were treated in the same way. Different additives including the lime, cement, emulsion, and the effect of the number of layers were considered. The bearing capacity ratio values (BCR), improvement ratio values (IR) and variation of load-settlement ratio obtained from the treated models were presented. The results showed that the treatment of geotextile has a great effect on the behavior of reinforced sand and thus bearing capacity. Also, the test results indicated that lime-treated geotextiles provided better improvement than other additives. The maximum improvement in the bearing capacity of square footing supported on treated geotextiles was found to be 75% compared with the pristine geotextiles.

Behaviour of geocomposite and geotextile reinforced soil bed- an experimental study

Soil reinforcements using geosynthetics have been utilized in many areas of geotechnical engineering. In this study, a series of model tests have been conducted to understand the influence of two different kinds of planner geosynthetics in a denser soil medium, and the effect of different parameters premediated the load-settlement characteristics have been evaluated under monotonic loading. The parameters premeditated in this investigation include the effects of the top layer location, size, and the number of reinforcing layers, which were articulated in a non-dimensional ratio as bearing capacity ratio (BCR). The test findings showed the possible benefit of using reinforcements on a sandy soil bed influenced by the configuration of the mattresses. An increasing trend of improvement has been observed irrespective of the type of planner geosynthetics with optimum reinforcement arrangements (u = 0.33B and b = 4). However, higher improvement was exhibited using geocomposite (GC) compared to geotextile (GT). Using optimum reinforcement arrangements, geocomposite shows more than a threefold increase in BCR, i.e., a 19.59 % incremental increase compared to geotextile. It is evident from the results that designed reinforcement arrangements have a high potential to improve soil-bearing capacity.

Experimental Study on Effect of Recycled Reinforced Concrete Waste on Mechanical Properties and Structural behaviour of the Sandy Soil

In recent years, constructing natural aggregates as a base layer for the roads has increased. Natural resources will run out as long as human consumption of them continues. Recycled concrete aggregate (RC) has thus emerged as a substitute material for the building of road base layers. Additionally, RC can be utilized to create interior city highways. The base layer for roads must have sufficient strength to support the working load on the pavement surface without damage deforming. As a result, the focus of this paper is on enhancing the structural performance of sandy soil reinforced with various RC percentages. The three key factors are relative soil density (Dr = 83 and 97%), recycled concrete aggregate reinforcing levels (RC = 0,5,10,15,20,25,30,40,50 and 100%), and reinforcement layer thickness (Rd = 0.0B, 0.5B, B, and 2B where B is the footing model width). Numerous laboratory experiments were conducted in order to examine the impact of important parameters on the properties of the mixtures. The plate bearing tests were carried out using a footing model (250 × 250 mm) inside a tank (1500 × 1500x1000 mm) to ascertain the stress–strain response, bearing capacity ratio (BCR), ultimate bearing capacity, and modulus of elasticity of the tested mixtures. It is clear that raising the RC has no effect on the diameters of the grains. It was found that as RC increased, the mixture's bulk density increased but specific gravity decreased. Maximum dry density rose as RC rose, whereas water content fell. It was noted that BCR unquestionably increased as RC increased for all RC levels and all values of settlement ratios. The appropriate reinforcing layer thickness is suggested to be no more than 2B. As the RC concentration in the sand and Rd increased, the difference between two pressure-settlement curves of densities 83% and 97% significantly decreased. Furthermore, when RC reaches 50%, two curves are roughly comparable. At RC = 50%, it is advised that the relative density of 83% is sufficient to produce the same behavior as the relative density of 97%. It was found that as RC and Rd grew, the tested mixtures' ultimate bearing capacity and elasticity modulus increased as well. A novel proposed formulas are developed to compute bearing capacity ratio, ultimate bearing capacity, and elasticity modulus of the tested mixtures taking into account the influence of RC, reinforcement layer depth, settlement ratio, and the relative density, and its results agree with the experimental results.

Field tests on partially geotextile encased stone column-supported embankment over silty clay

Various researchers have highlighted that geosynthetic-encased stone columns could be used in place of stone columns (SCs) in very soft soil. In this study, field load tests are performed on individual partially geotextile-encased stone columns (pESCs), individual stone columns (SCs), and a field embankment reinforced with pESCs and SCs in silty clay. Although the material cost of pESCs is designed to be comparable to that of SCs, the tests reveal that pESCs display a higher allowable bearing capacity and stress concentration ratio and less residual settlement than SCs. The embankment reinforced by pESCs is found to incur fewer lateral displacements, while there is no improvement in the drainage performance during the construction period compared to the SCs. For the pESCs, 51–66% of the pressure acting on the top of the column propagates to a depth of z = 1.2 m, wheras, for the SCs, it is only 21–55%. Furthermore, to estimate group behaviour, the ultimate bearing capacity of an individual pile composite ground can be extrapolated. However, individual pESCs achieve much higher stress concentration ratios than the pESC group.

Influence of geogrid arrangement on the bearing capacity of a granular soil on physical models and its comparison to theoretical equations

This study presents an analysis of the influence of geogrid distribution on the bearing capacity of granular soils. For this purpose, the bearing capacity is compared based on 3 arrangements, uniform, trapezoidal, and inverted trapezoidal, with 2 types of geogrids, biaxial and multiaxial, under the application of an axial load. The tests performed were analyzed in three forms in which the trapezoidal distribution was the best arrangement for biaxial and multiaxial geogrids. The first analysis considers the peaks for each stress–strain curve, the trapezoidal distribution increases the bearing capacity by 36% and 33% for biaxial and multiaxial geogrids, respectively. The second analysis considers a settlement ratio (s/B) of 10%, which had an average increment of 30.5% for the two types of geogrids. The third analysis considers a 20% of s/B ratio, which showed a 56% and 81% of bearing capacity ratio (BCR) increase for biaxial and multiaxial geogrids respectively. From an economical and environmental analysis, the trapezoidal distribution saves 7% of material compared to the traditional uniform distribution. The comparison between physical and numerical models with theoretical equations is presented.

Increasing the Bearing Capacity of Shallow Foundations on Soft Soil After the Installation of Micro-Piles

The bearing capacity of shallow foundations on soft soils can generally be estimated based on Local Shear Failure (Terzaghi theory). Several researchers previously stated that the installation of micro-piles on the failure area (slide) can increase the shear strength of the soil. This can be followed up by providing micro-pile reinforcement to prevent lateral soil movement. Therefore, this research was conducted to increase the bearing capacity of shallow foundations on medium-consistency soft clay soils that have been reinforced with micro piles. The research was conducted using modeling in the laboratory with a scale of 1:30. The soil sample used was kaolin clay made from slurry made from kaolin powder with a water content (wc = 1.77 LL), liquid limit (LL = 62.35%) and sample diameter (d = 33 cm). The slurry was formed by compacting at a medium consistency level with an undrained cohesion value (cu = 0.397 kg cm-2). The micro-pile material in the form of apus bamboo was installed, varying in diameter (d) 0.2 cm (0.027 B), 0.3 cm (0.04 B), and 0.5 cm (0.07 B); sum (n) 4, 9, 16, and 25; and length (L) 10 cm (1.33B), 13 cm (1.73B), and 16 cm (2.13B) micro-piles. While the foundation model uses a squarefoundation B x B with B = 7.5 cm. The tests were carried out before and after the micro-piles were reinforced with a soil shear failure test. The results showed that a decrease of 0.1B caused an increase in the ultimate bearing capacity of the micro-pile (qult-empirical, 0.1B) from the ultimate bearing capacity before installing the micro-pile. This value is then used to determine the ultimate bearing capacity ratio so that Rq,0.1B = qult-empirical,0.1B/qult-Terzaghi with the optimum bearing capacity ratio occurring at Rq,0.1B with n3 = 16, d2 = 0.04B, L2 = 1.73B.

Bearing capacity of footings on geosynthetic-reinforced soils under combined loading

In this study, the ultimate bearing capacity of shallow strip footings resting on a geosynthetic-reinforced soil mass subjected to inclined and eccentric combined loading is rigorously examined through the well-established method of lower bound limit analysis (LA) in conjunction with finite element (FE) and second-order cone programming (SOCP). Lower bound limit analysis formulation is modified to consider the ultimate tensile force of the geosynthetic layer in the soil mass so as to account for both pullout (sliding) and rupture (structural) modes of reinforcement failure. The effects of several parameters, including the embedment depth (u) and the ultimate tensile strength (Tu) of the geosynthetic layer along with load inclination angle (α) and load eccentricity (e), on the bearing capacity ratio (BCR) and failure envelopes of the overlying shallow foundation are examined and discussed. The results generally show a marked increase in the ultimate bearing capacity of the surface footing against combined loading with the inclusion of a single geosynthetic layer. Results also reveal that a second intermediate reinforcement might be required to bear a dual performance against both vertical concentric and combined loading scenarios so as to more effectively support the footing.