Effect of surface crack on the bearing capacity of strip footing placed on rock mass

In hilly regions,the existence of surface cracks in rock mass induces a potential threat to structural stability.Thus,the present research aims to explore the impact of surface cracks on the loadbearing capacity of strip footing placed on the rock mass.By taking into account the various boundary constraints across the surface of crack edges,the study investigates the presence of two categories of surface cracks,namely(1)separated crack,and(2)fine crack.The lower bound limit analysis is employed in conjunction with the finite element method(LBFELA)to conduct the numerical analysis.In order to evaluate rock mass yielding,the power conic programming(PCP)method is utilized to implement the generalized Hoek-Brown(GHB)failure criterion.The stability of the strip footing is analyzed by determining the bearing capacity factor(Nσγ),which is presented in the form of design charts by varying the strength parameters of rock,including the Geological Strength Index(GSI),Hoek-Brown material parameter(mi),Disturbance factor(D),and Normalised Uniaxial Compressive Strength(σci/γB),whereγis the unit weight of rock mass,and B is the width of strip footing.The study also investigates the impact of cracks on strip footings,considering different positions of the crack(LC)and depths of the crack(DC).The results demonstrate that the influence of the fine crack is only noticeable until the LC/B ratio reaches 6.However,for the separated crack,its impact remains significant even when the LC/B ratio exceeds 16.The appearance of fine crack at the edge of the footing results in a decrease in the magnitude Nσγof up to 45%,indicating a substantial reduction in the stability of the footing.The failure patterns are presented and discussed in detail for various cases in this study to examine the effect of surface cracks on the strip footing and to address the extent of the plastic collapse.

Developing a novel big dataset and a deep neural network to predict the bearing capacity of a ring footing

The accurate prediction of the bearing capacity of ring footings,which is crucial for civil engineering projects,has historically posed significant challenges.Previous research in this area has been constrained by considering only a limited number of parameters or utilizing relatively small datasets.To overcome these limitations,a comprehensive finite element limit analysis(FELA)was conducted to predict the bearing capacity of ring footings.The study considered a range of effective parameters,including clay undrained shear strength,heterogeneity factor of clay,soil friction angle of the sand layer,radius ratio of the ring footing,sand layer thickness,and the interface between the ring footing and the soil.An extensive dataset comprising 80,000 samples was assembled,exceeding the limitations of previous research.The availability of this dataset enabled more robust and statistically significant analyses and predictions of ring footing bearing capacity.In light of the time-intensive nature of gathering a substantial dataset,a customized deep neural network(DNN)was developed specifically to predict the bearing capacity of the dataset rapidly.Both computational and comparative results indicate that the proposed DNN(i.e.DNN-4)can accurately predict the bearing capacity of a soil with an R2 value greater than 0.99 and a mean squared error(MSE)below 0.009 in a fraction of 1 s,reflecting the effectiveness and efficiency of the proposed method.

Bearing Capacity Analysis of Spread Footing on Massif in the “Corniche Ouest” of the Dakar Peninsula (Senegal, West Africa)

This study presents various approaches to calculating the bearing capacity of spread footings applied to the rock mass of the western corniche at the tip of the Dakar peninsula. The bearing capacity was estimated using empirical, analytical and numerical approaches based on the parameters of the rock mass and the foundation. Laboratory tests were carried out on basanite, as well as on the other facies detected. The results of these studies give a range of allowable bearing capacity values varying between 1.92 and 11.39 MPa for the empirical methods and from 7.13 to 25.50 MPa for the analytical methods. A wide dispersion of results was observed according to the different approaches. This dispersion of results is explained by the use of different rock parameters depending on the method used. The allowable bearing capacity results obtained with varying approaches of calculation remain admissible to support the loads. On the other hand, the foundation calculations show acceptable settlement of the order of a millimeter for all the layers, especially in the thin clay layers resting on the bedrock at shallow depths, where the rigidity of the rock reduces settlement.

Nonlinear Pushover Analysis of the Influences on RC Footing for the External Elevator Well

In contemporary society, reducing carbon dioxide emissions and achieving sustainable development are paramount goals. One effective approach is to preserve existing RC (Reinforced Concrete) buildings rather than demolishing them for new construction. However, a significant challenge arises from the lack of elevator designs in many of these existing RC buildings. Adding an external elevator becomes crucial to solving accessibility issues, enhancing property value, and satisfying modern residential buildings using convenient requirements. However, the structural performance of external elevator wells remains understudied. This research is designed by the actual external elevator project into existing RC buildings in Jinzhong Rd, Shanghai City. Specifically, this research examines five different external elevator wells under nonlinear pushover analysis, each varying in the height of the RC (Reinforced Concrete) footing. By analyzing plastic hinge states, performance points, capacity curves, spectrum curves, layer displacement, and drift ratio, this research aims to provide a comprehensive understanding of how these structures of the external elevator well respond to seismic events. The findings are expected to serve as a valuable reference for future external elevator projects, ensuring the external elevator designs meet the seismic requirements. By emphasizing seismic resistance in the design phase, the research aims to enhance the overall safety and longevity of external elevator systems integrated into existing RC buildings.

Foot reflexology in autoimmune diseases:Effectiveness and mechanisms

Foot reflexology(FR)is a Chinese-originated and non-invasive complementary therapy increasingly used by functional,alternative and para-medical professionals.Enhance attempts are made to study FR in non-functional organic conditions.The present invited Editorial discusses the application of FR in autoimmune diseases(AD),highlighting a few successful studies demonstrating symptomatic relief and objective improvements.Despite promising results,the FR domain remains under-investigated and an urgent need to confirm and understand the effect of FR in chronic diseases,including AD,is highly recommended.

Is it possible to foot reflexology for infants with sensorineural hearing loss?

Foot reflexology is a non-invasive and safe complementary therapy that works by massaging the reflex zones of the feet and exerts systemic or whole-body regulation through meridian nerve conduction.This therapy is commonly used in the treatment of various conditions such as autism and Parkinson's disease.However,there is limited reporting on the use of foot reflexology therapy for infants with sensorineural hearing loss(SNHL).Currently,there is no definitive conclusion on how foot reflexology therapy can influence hearing.This editorial holds some guiding significance regarding this clinical issue.The aim is to present physiological evidence of how foot reflexology therapy can impact infants with SNHL,thereby enhancing clinician’s awareness of foot reflexology in treating infants with SNHL.

Role of macrophage polarization in diabetic foot ulcer healing:A bibliometric study

BACKGROUND Diabetic foot ulcers(DFUs)are a significant contributor to disability and mortality in diabetic patients.Macrophage polarization and functional regulation are promising areas of research and show therapeutic potential in the field of DFU healing.However,the complex mechanism,the difficulty in clinical translation,and the large heterogeneity present significant challenges.Hence,this study was to comprehensively analyze the publication status and trends of studies on macrophage polarization and DFU healing.AIM To examine the relevant literature on macrophage polarization in DFU healing.METHODS A bibliometric analysis was conducted using the Web of Science database.Relevant literature was retrieved from the Web of Science Core Collection database between 2013 to 2023 using literature visualization and analysis software(VOSviewer and CiteSpace)and bibliometric online platforms.The obtained literature was then subjected to visualization and analysis of different countries/regions,institutions,journals,authors,and keywords to reveal the research’s major trends and focus.RESULTS The number of publications on the role of macrophage polarization in DFU healing increased rapidly from 2013 to 2023,especially in the latter period.Chinese researchers were the most prolific in this field,with 217 publications,while American researchers had been engaged in this field for a longer period.Qian Tan of Nanjing Drum Tower Hospital and Qian Ding of Nanjing University were the first to publish in this field.Shanghai Jiao Tong University was the institution with the most publications(27).The keywords“bone marrow”,“adjustment,replacement,response,tissue repair”,and“activation,repair,differentiation”appeared more frequently.The study of macrophage polarization in DFU healing focused on the regulatory mechanism,gene expression,and other aspects.CONCLUSION This study through the bibliometric method reveals the research trends and development trends in this field of macrophage polarization in DFU healing from 2013 to 2023 in the Web of Science Core Collection database.The key hotspots in this field mainly include the regulation of macrophage activation,gene expression,wound tissue repair,and new wound materials.This study provides references for future research directions.

Diabetic foot attack:Managing severe sepsis in the diabetic patient

Diabetic foot attack(DFA)is the most severe presentation of diabetic foot disease,with the patient commonly displaying severe sepsis,which can be limb or life threatening.DFA can be classified into two main categories:Typical and atypical.A typical DFA is secondary to a severe infection in the foot,often initiated by minor breaches in skin integrity that allow pathogens to enter and proliferate.This form often progresses rapidly due to the underlying diabetic pathophysiology of neuropathy,microvascular disease,and hyperglycemia,which facilitate infection spread and tissue necrosis.This form of DFA can present as one of a number of severe infective pathologies including pyomyositis,necrotizing fasciitis,and myonecrosis,all of which can lead to systemic sepsis and multiorgan failure.An atypical DFA,however,is not primarily infection-driven.It can occur secondary to either ischemia or Charcot arthropathy.Management of the typical DFA involves prompt diagnosis,aggressive infection control,and a multidisciplinary approach.Treatment can be guided by the current International Working Group on the Diabetic Foot/Infectious Diseases Society of America guidelines on diabetic foot infections,and the combined British Orthopaedic Foot and Ankle Society-Vascular Society guidelines.This article highlights the importance of early recognition,comprehensive management strategies,and the need for further research to establish standardized protocols and improve clinical outcomes for patients with DFA.

Acellular fish skin grafts in diabetic foot ulcer care:Advances and clinical insights

Diabetic foot ulcers(DFUs)represents a significant public health issue,with a rising global prevalence and severe potential complications including amputation.Traditional treatments often fall short due to various limitations such as high recurrence rates and extensive resource utilization.This editorial explores the innovative use of acellular fish skin grafts as a transformative approach in DFU management.Recent studies and a detailed case report highlight the efficacy of acellular fish skin grafts in accelerating wound closure,reducing dressing changes,and enhancing patient outcomes with a lower socio-economic burden.Despite their promise,challenges such as limited availability,patient acceptance,and the need for further research persist.Addressing these through more extensive randomized controlled trials and fostering a multidisciplinary treatment approach may optimize DFU care and reduce the global health burden associated with these complex wounds.

Risk factors and a predictive model of diabetic foot in hospitalized patients with type 2 diabetes

BACKGROUND The risk factors and prediction models for diabetic foot(DF)remain incompletely understood,with several potential factors still requiring in-depth investigations.AIM To identify risk factors for new-onset DF and develop a robust prediction model for hospitalized patients with type 2 diabetes.METHODS We included 6301 hospitalized patients with type 2 diabetes from January 2016 to December 2021.A univariate Cox model and least absolute shrinkage and selection operator analyses were applied to select the appropriate predictors.Nonlinear associations between continuous variables and the risk of DF were explored using restricted cubic spline functions.The Cox model was further employed to evaluate the impact of risk factors on DF.The area under the curve(AUC)was measured to evaluate the accuracy of the prediction model.RESULTS Seventy-five diabetic inpatients experienced DF.The incidence density of DF was 4.5/1000 person-years.A long duration of diabetes,lower extremity arterial disease,lower serum albumin,fasting plasma glucose(FPG),and diabetic nephropathy were independently associated with DF.Among these risk factors,the serum albumin concentration was inversely associated with DF,with a hazard ratio(HR)and 95%confidence interval(CI)of 0.91(0.88-0.95)(P<0.001).Additionally,a U-shaped nonlinear relationship was observed between the FPG level and DF.After adjusting for other variables,the HRs and 95%CI for FPG<4.4 mmol/L and≥7.0 mmol/L were 3.99(1.55-10.25)(P=0.004)and 3.12(1.66-5.87)(P<0.001),respectively,which was greater than the mid-range level(4.4-6.9 mmol/L).The AUC for predicting DF over 3 years was 0.797.CONCLUSION FPG demonstrated a U-shaped relationship with DF.Serum albumin levels were negatively associated with DF.The prediction nomogram model of DF showed good discrimination ability using diabetes duration,lower extremity arterial disease,serum albumin,FPG,and diabetic nephropathy(Clinicaltrial.gov NCT05519163).

Evaluating the effectiveness of ultrasound-assisted wound debridement in managing diabetic foot ulcers:A systematic review and meta-analysis

BACKGROUND Diabetic foot ulcers(DFUs)present a significant clinical challenge due to their high prevalence and profound impact on morbidity.Ultrasound-assisted wound debridement(UAWD)has emerged as a potential therapeutic modality to improve healing outcomes in DFU management.AIM To evaluate the efficacy of UAWD in treating DFUs on wound closure rates,treatment duration,and quality of life outcomes.METHODS This systematic review and meta-analysis followed PRISMA guidelines,systematically searching PubMed,Embase,Web of Science,and the Cochrane Library with no date restrictions.Randomized controlled trials(RCTs)that evaluated the efficacy of UAWD in DFU treatment were included.Data were independently extracted by two reviewers,with discrepancies resolved through consensus or third-party consultation.The risk of bias was assessed using the Cochrane tool.χ2 and I2 statistics assessed heterogeneity,informing the use of fixed or random-effects models for meta-analysis,supplemented by sensitivity analysis and publication bias assessment through funnel plots and Egger's test.RESULTS From 1255 articles,seven RCTs met the inclusion criteria.The studies demonstrated that UAWD significantly reduced DFU healing time(standardized mean difference=-0.78,95%CI:-0.97 to-0.60,P<0.001)and increased healing rates(odds ratio=9.96,95%CI:5.99 to 16.56,P<0.001)compared to standard care.Sensitivity analysis confirmed the stability of these results,and no significant publication bias was detected.CONCLUSION UAWD is a promising adjunctive treatment for DFUs,significantly reducing healing times and increasing healing rates.These findings advocate for the integration of UAWD into standard DFU care protocols.

Comprehensive review on diabetic foot ulcers and neuropathy: Treatment, prevention and management

Diabetic foot(DF)is a major public health concern.As evident from numerous previous studies,supervision of DF ulcer(DFU)is crucial,and a specific quality check-up is needed.Patients should be educated about glycaemic management,DFUs,foot lesions,proper care for injuries,diet,and surgery.Certain reasonably priced treatments,such as hyperbaric oxygen and vacuum-assisted closure therapy,are also available for DFUs,along with modern wound care products and techniques.Nonetheless,DF care(cleaning,applying antimicrobial cream when wounded,and foot reflexology),blood glucose monitoring to control diabetes,and monthly or quarterly examinations in individuals with diabetes are effective in managing DFUs.Between 50%and 80%of DF infections are preventable.Regardless of the intensity of the lesion,it needs to be treated carefully and checked daily during infection.Tissue regeneration can be aided by cleaning,dressing,and application of topical medicines.The choice of shoes is also important because it affects blood circulation and nerve impulses.In general,regular check-ups,monitoring of the patient’s condition,measuring blood glucose levels,and providing frequent guidance regarding DFU care are crucial.Finally,this important clinical problem requires involvement of multiple professionals to properly manage it.

Correlation between key indicators of continuous glucose monitoring and the risk of diabetic foot

BACKGROUND Continuous glucose monitoring(CGM)metrics,such as time in range(TIR)and glycemic risk index(GRI),have been linked to various diabetes-related complications,including diabetic foot(DF).AIM To investigate the association between CGM-derived indicators and the risk of DF in individuals with type 2 diabetes mellitus(T2DM).METHODS A total of 591 individuals with T2DM(297 with DF and 294 without DF)were enrolled.Relevant clinical data,complications,comorbidities,hematological parameters,and 72-hour CGM data were collected.Logistic regression analysis was employed to examine the relationship between these measurements and the risk of DF.RESULTS Individuals with DF exhibited higher mean blood glucose(MBG)levels and increased proportions of time above range(TAR),TAR level 1,and TAR level 2,but lower TIR(all P<0.001).Patients with DF had significantly lower rates of achieving target ranges for TIR,TAR,and TAR level 2 than those without DF(all P<0.05).Logistic regression analysis revealed that GRI,MBG,and TAR level 1 were positively associated with DF risk,while TIR was inversely correlated(all P<0.05).Achieving TIR and TAR was inversely correlated with white blood cell count and glycated hemoglobin A1c levels(P<0.05).Additionally,achieving TAR was influenced by fasting plasma glucose,body mass index,diabetes duration,and antidiabetic medication use.CONCLUSION CGM metrics,particularly TIR and GRI,are significantly associated with the risk of DF in T2DM,emphasizing the importance of improved glucose control.

一种可用于Footing效应模拟的ICP刻蚀模型

电感耦合等离子体(ICP)刻蚀在目前的硅微机械加工中应用十分广泛。在这一加工过程中,存在着影响结构拓扑特性、被加工结构性能的一些效应,SOI结构中的Footing效应就是其中之一。本文在利用一种改进的复合交替深刻蚀(TMDE)模型对ICP刻蚀表面进行建模及数值模拟的基础上,根据Footing效应的实验表现特征,设定类高斯分布的表面描述方程。同时借助实验数据确定了表面描述方程中的参数,添加了一种简单有效的Footing效应模拟模块。最后对Footing效应刻蚀表面进行模拟,并得到与实验较为一致的表面模拟结果。

Experimental Study on the Footing Effect for SOG Structures Using DRIE

This paper experimentally studies the effects of the conductivity of a silicon wafer and the gap height between silicon structures and glass substrate on the footing effect for silicon on glass （SOG） structures in the deep reactive ion etching （DRIE） process. Experiments with gap heights of 5,20, and 50μm were carried out for performance comparison of the footing effect. Also,two kinds of silicon wafers with resistivity of 2-4 and 0.01-0. 0312Ω· cm were used for the exploration. The results show that structures with resistivity of 0.01 - 0. 0312Ω· cm have better topography than those with resistivity of 2-4Ω· cm; and structures with 50μm-high gaps between silicon structures and glass substrate suffer some- what less of a footing effect than those with 20μm-high gaps,and much less than those with Stem-high gaps. Our theoretical analysis indicates that either the higher conductivity of the silicon wafer or a larger gap height between silicon structures and glass substrate can suppress footing effects. The results can contribute to the choice of silicon type and optimum design for many microsensors.

Study on Failure Mechanism and Bearing Capacity of Three-Dimensional Rectangular Footing Subjected to Combined Loading

This paper presents two kinematic failure mechanisms of threc-dimensional rectangular footing resting on homogeneous undrained clay foundation under uniaxial vertical loading and uniaxial moment loading. The failure mechanism under vertical loading comprises a plane strain Prandti-type mechanism over the central part of the longer side, and the size of the mechanism gradually reduces at the ends of the longer side and over the shorter side as the corner of rectangular footing is being approached where the direction of soil motion remains normal to each corresponding side respectively. The failure mechanism under moment loading comprises a plane strain scoop sliding mechanism over the central part of the longer side, and the radius of scoop sliding mechanism increases linearly at the ends of the longer side. On the basis of the kinematic failure mechanisms mentioned above, the vertical ultimate bearing capacity and the ultimate bearing capacity against moment or moment ultimate bearing capacity are obtained by use of upper bound limit analysis theory. At the same time, numerical analysis results, Skempton＇ s results and Salgado et al. ＇s results are compared with this upper bound solution. It shows that the presented failure mechanisms and plastic limit analysis predictions are validated. In order to investigate the behaviors of undrained clay foundation beneath the rectangular footing subjected to the combined loadings, numerical analysis is adopted by virtue of the general-purpose FEM software ABAQUS, where the clay is assumed to obey the Mohr-Coulomb yielding criterion. The failure envelope and the ultimate bearing capacity are achieved by the numerical analysis results with the varying aspect ratios from length L to breadth B of the rectangular footing. The failure mechanisms of rectangular footing which are subjected to the combined vertical loading V and horizontal loading H （Vertical loading V and moment loading M, and horizontal loading H and moment loading M respectively are observed in the finite element analysis. ） is explained by use of the upper bound plasticity limit analysis theory. Finally, the reason of eccentricity of failure envelope in H-M loading space is given in this study, which can not be explained by use of the traditional ＇ swipe test＇.

Assessment of bearing capacity of interfering strip footings located near sloping surface considering artificial neural network technique

The bearing capacity of interfering footings located near the slope face suffers from reduced bearing capacity due to the formation of the curtailed passive zone. Depending upon the position of the footing, their spacing and steepness of the slope different extents of bearing capacity reduction can be exhibited. A series of finite element investigation has been done with the aid of Plaxis 3 D v AE.01 to elucidate the influence of various geotechnical and geometrical parameters on the ultimate bearing capacity of interfering surface strip footings located at the crest of the natural soil slope. Based on the large database obtained from the numerical simulation, a6-8-1 Artificial Neural Network architecture has been considered for the assessment of the ultimate bearing capacity of interfering strip footings placed on the crest of natural soil slope. Sensitivity analyses have been conducted to establish the relative significance of the contributory parameters, which exhibited that for the stated problem, apart from shear strength parameters, the setback ratio and spacing of footing are the prime contributory parameters.

Settlement predictions of footings on sands using probabilisticanalysis

The design of footings on sands is often controlled by settlement rather than bearing capacity.Therefore,settlement predictions are essential in the design of shallow foundations.However,predicted settlements of footings are highly dependent on the chosen elastic modulus and the used method.This paper presents the use of probabilistic analysis to evaluate the variability of predicted settlements of footings on sands,focusing on the load curve(predicted settlements)characterization.Three methodologies,the first-and second-order second-moment(FOSM and SOSM),and Monte Carlo simulation(MCS),for calculating the mean and variance of the estimated settlements through Schmertmann(1970)’s equation,are presented and discussed.The soil beneath the footing is treated as an uncorrelated layered material,so the total settlement and variance are found by adding up the increments of the layers.The deformability modulus(ESi)is considered as the only independent random variable.As an example of application,a hypothetical case of a typical subsoil in the state of Espirito Santo,southeast of Brazil,is evaluated.The results indicate that there is a significant similarity between the SOSM and MCS methods,while the FOSM method underestimates the results due to the non-consideration of the high-order terms in Taylor’s series.The contribution of the knowledge of the uncertainties in settlement prediction can provide a safer design.

采用防Footing效应工艺加工的SOI微加速度计

为了解决深刻蚀绝缘体上硅(silicon on insulator,SOI)材料时存在的横向刻蚀(Footing)效应,在背腔释放SOI微机电系统(micro electro mechanical system,MEMS)工艺基础上,提出并实现了一种改进的利用背面保护电极抑制Footing效应的工艺方案.在SOI圆片上生长SiO2和Si3N4掩模材料并图形化后,背面腐蚀支撑层Si至掩埋层SiO2.去除掩埋层SiO2后,完成正面Al电极和背面保护Al电极的溅射.深反应离子干法刻蚀SOI圆片形成结构,再腐蚀背面Al薄膜完成结构释放.基于该工艺,对结构层厚度为80μm的采用双端固支梁的SOI微加速度计的结构进行设计与仿真、器件加工和最终的性能测试.加速度计在±1 g(g=9.8 m/s2)范围内的灵敏度和非线性度分别为106.7 mV/g和0.1%.实验结果表明,该改进工艺方案可以有效抑制Footing效应对器件结构的损伤,提高加工的可靠性.

Depth factors for undrained bearing capacity of circular footing by numerical approach

The undrained vertical bearing capacity of embedded foundation has been extensively studied using analytical and numerical methods.Through comparing the results of a circular embedded foundation in the literature,a significant difference between the bearing capacity factors and depth factors is observed.Based on the previous research findings,numerical computations using FLAC code are carried out in this study to evaluate the undrained bearing capacity of circular foundations with embedment ratios up to five for different base and side foundation roughness conditions.Unlike the foundation base,the roughness of the foundation side has a significant effect on the bearing capacity.The comparison of the present results with numerical studies available in the literature shows that the discrepancy is related to the procedures used to simulate the foundation side interface conditions and to the estimation of the bearing capacity.