Studia Geotechnica et Mechanica最新文献_第3页

Reliability of Methods for Determination of Stress History Parameters in Soils 土壤应力历史参数测定方法的可靠性

Studia Geotechnica et Mechanica Pub Date : 2023-10-07 DOI: 10.2478/sgem-2023-0017

Małgorzata Wdowska, Mirosław J. Lipiński

{"title":"Reliability of Methods for Determination of Stress History Parameters in Soils","authors":"Małgorzata Wdowska, Mirosław J. Lipiński","doi":"10.2478/sgem-2023-0017","DOIUrl":"https://doi.org/10.2478/sgem-2023-0017","url":null,"abstract":"Abstract Stress history acquired by any cohesive soil influences, to a large extent, three groups of fundamental properties indispensable in geotechnical design i.e. state of soil, shear strength, and stiffness characteristics. The basic stress history parameter (from which other parameters are derived) determined directly from laboratory tests is a preconsolidation stress σ′p. Since the first method proposed by Casagrande in 1936, value σ′p is determined in the oedometer test as a border between overconsolidated (OC) and normally consolidated (NC) zones. Approach based on division between predominantly elastic, (recoverable) strain, and plastic (irrecoverable) strain is a main principle of several methods of σ′p determination, which have been proposed over the past eighty-six years. Accumulated experiences have revealed that any laboratory procedure based on the oedometer test does not provide realistic value of preconsolidation stress, especially in heavy preconsolidated soils. The major reason for that results from the fact that the mechanism responsible for natural overconsolidation is more complicated than mechanical preloading. Therefore, there is a necessity to reevaluate effectiveness of standard methods and look for another solution of evaluation yield stress σ′Y in natural soils. This article presents the comparison between σ′Y determined for various soils with use of standard methods based on conventional oedometer test and yield stress determined on the basis of alternative procedures. The latter are represented by various approaches as e.g. based on SHANSEP procedure or initial shear modulus and others. The most promising among these alternative methods is a new concept based on dilatancy phenomenon that takes place during shearing of a dense soil. The parameter reflecting stress history is derived from pore pressure response and is based on characteristic values of Skempton's parameter A record. Consistency of data concerning stress history parameters profile obtained for deep subsoil on the basis of various methods is shown for comparison.","PeriodicalId":44626,"journal":{"name":"Studia Geotechnica et Mechanica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135253849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Second-Order Work Criterion in the Stability Analysis of an Earth Dam Subjected to Seepage 渗流作用下土坝稳定性分析的二阶功准则

Studia Geotechnica et Mechanica Pub Date : 2023-10-01 DOI: 10.2478/sgem-2023-0015

Krzysztof Sternik

{"title":"Second-Order Work Criterion in the Stability Analysis of an Earth Dam Subjected to Seepage","authors":"Krzysztof Sternik","doi":"10.2478/sgem-2023-0015","DOIUrl":"https://doi.org/10.2478/sgem-2023-0015","url":null,"abstract":"Abstract Failure may take different forms: reaching the Mohr–Coulomb limit stress condition is accompanied by yielding, strain localisation may occur in shear, compaction or dilatant bands, arbitrary large strain and loss of strength may be accompanied by a field of chaotic displacements of soil particles. Failure is also related to material instability. It takes place when there is a loss of uniqueness of constitutive relationships. It has been found that instability domains exist strictly inside the Mohr–Coulomb failure surface. Material instability can be detected by local Hill's criterion, that is the second-order work at a point. Results of a coupled hydro-mechanical finite element analysis of an ‘earth dam – subgrade’ system at changing hydraulic boundary conditions have been presented in the article. Normalised values of the second-order work and factor of safety values by the shear strength reduction procedure for corresponding stages of the analysis were calculated. It has been shown that the value of the safety factor corresponds to the values of the second-order work. The analysis results show that a decrease in the value of the safety factor is accompanied by a decrease in the value of the second-order work until negative values occur at some points.","PeriodicalId":44626,"journal":{"name":"Studia Geotechnica et Mechanica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135373460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of the Addition of Dispersed Reinforcement on the Resilient Modulus of Slightly Cemented Non-Cohesive Soil 分散配筋对微胶结非粘性土弹性模量的影响

Studia Geotechnica et Mechanica Pub Date : 2023-09-30 DOI: 10.2478/sgem-2023-0013

Mariola Wasil, Patryk Dobrzycki, Katarzyna Zabielska-Adamska

{"title":"Effect of the Addition of Dispersed Reinforcement on the Resilient Modulus of Slightly Cemented Non-Cohesive Soil","authors":"Mariola Wasil, Patryk Dobrzycki, Katarzyna Zabielska-Adamska","doi":"10.2478/sgem-2023-0013","DOIUrl":"https://doi.org/10.2478/sgem-2023-0013","url":null,"abstract":"Abstract The aim of this article is to determine the effect of the addition of dispersed reinforcement on the resilient modulus of non-cohesive soil used as material for improved subgrade or subbase course of the pavement structure. Resilient modulus ( M r ) is a parameter used in road construction, which characterises soil subgrade or base aggregates stiffness in flexible pavement subjected to the traffic load. This article presents laboratory test results of non-cohesive coarse material (gravelly sand – grSa – without fines) with the addition of 1.5% cement and dispersed reinforcement – polypropylene fibres in lengths of 12, 18 and 40 mm. Tests were conducted on the samples with various percentages of fibres (0, 0.2 and 0.3%) relating to the dry mass of the soil. Samples were compacted according to the standard Proctor (SP) and modified Proctor (MP) methods. Main laboratory tests were conducted in the triaxial apparatus enabling testing samples subjected to cyclic loads according to AASHTO T307 standard. Resilient modulus was determined after 7 and 28 days of curing. The results indicate the influence of fibre amount, fibre length, and curing time on the M r of the soil modified with 1.5% of cement. The obtained results were also influenced by the method of compaction. The addition of polypropylene fibres decreases the resilient modulus of soil stabilised by 1.5% of cement. The best results of dispersive reinforcement were obtained for samples containing 0.3% of fibres with a length of 18 mm, compacted by the MP methods.","PeriodicalId":44626,"journal":{"name":"Studia Geotechnica et Mechanica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136342175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of Soft Soil Samples Quality on the Compressibility and Undrained Shear Strength – Seven Lessons Learned From the Vistula Marshlands 软土试样质量对压缩性和不排水抗剪强度的影响——以维斯瓦湿地为例

Studia Geotechnica et Mechanica Pub Date : 2023-09-30 DOI: 10.2478/sgem-2023-0012

Jakub Konkol

{"title":"Influence of Soft Soil Samples Quality on the Compressibility and Undrained Shear Strength – Seven Lessons Learned From the Vistula Marshlands","authors":"Jakub Konkol","doi":"10.2478/sgem-2023-0012","DOIUrl":"https://doi.org/10.2478/sgem-2023-0012","url":null,"abstract":"Abstract This technical article presents the influence of sample quality on the compressibility parameters and undrained shear strength ( c u ) of soft soils from the Vistula Marshlands. The analysis covers: (1) quality of soft soil according to three criteria: void ratio (Δ e / e 0 index), volumetric strain (Δ ɛ v ) and C r / C c ratio; (2) influence of storage time on quality; (3) influence of sample quality on undrained shear strength ( c u ), and (4) reliability of compression and undrained shear strength parameters estimation. The sample quality of three different soft soils (peat, organic clays, and organic silts) was investigated using dataset of geotechnical investigations from the Vistula Marshlands. The reliability of oedometer tests and compressibility parameters determination was shown. Different undrained shear strength estimates (from lab and field tests) were juxtaposed with sample quality. In situ estimates of undrained shear strength were compared with results of triaxial tests and direct simple shear test on reconstituted samples as well as SHANSEP estimates. The results of research are grouped in seven lessons. The most important outcomes are: (1) the quality of samples is at best moderate or poor and there is no significant influence of storage time on sample quality, (2) regardless of testing method, the undrained shear strength natural variability of the Vistula Marshlands soft soils is between 20% and 50% depending on deposit depth and soil type, (3) the most accurate estimation of undrained shear strength can be obtained from field vane test (FVT) while unconsolidated, undrained compression (UUC) triaxial tests should be avoided, (4) SHANSEP approach can be considered as a valuable estimate of c u (next to the FVTs), which additionally allows in relatively easy way to establish lower and upper bounds of c u .","PeriodicalId":44626,"journal":{"name":"Studia Geotechnica et Mechanica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136280609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Estimation of Screw Displacement Pile-Bearing Capacity Based on Drilling Resistances 基于钻孔阻力的螺旋位移桩承载力估算

Studia Geotechnica et Mechanica Pub Date : 2023-09-30 DOI: 10.2478/sgem-2023-0014

Adam Krasiński

{"title":"Estimation of Screw Displacement Pile-Bearing Capacity Based on Drilling Resistances","authors":"Adam Krasiński","doi":"10.2478/sgem-2023-0014","DOIUrl":"https://doi.org/10.2478/sgem-2023-0014","url":null,"abstract":"Abstract This article presents an engineering, empirical method of estimating the bearing capacity and settlement characteristics Q-s of screw displacement piles and columns, based on soil resistance encountered during the drilling to form piles/columns in the ground. The method was developed on the basis of correlation analyses of the test results of 24 piles made during the “DPDT-Auger” research project (Krasiński et al., 2022a). In the proposed method, the load capacity of a screw displacement pile is estimated using two main parameters of auger screwing resistance: torque M T and the number of auger rotations per depth unit n R . The method applies to piles and columns made with a standard screw displacement pile (SDP) auger and with the proprietary, prototype DPDT ( displacement pile drilling tool ) aguer, patented in Poland (2020). Based on the estimated ultimate capacities of the pile shaft and base, an approximate method of predicting the pile settlement characteristics Q-s was also proposed, using the transfer function method. This article describes a correlation procedure of field test results together with their statistical analysis and presents a method of estimating the pile-bearing capacity based on correlation results. A calculation example is also provided. The conclusion looks at the useful practical applications that could be found for the proposed method.","PeriodicalId":44626,"journal":{"name":"Studia Geotechnica et Mechanica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136280295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Stress–dilatancy behaviour of remoulded Fujinomori clay 重塑藤森黏土的应力-剪胀特性

Studia Geotechnica et Mechanica Pub Date : 2023-09-13 DOI: 10.2478/sgem-2023-0010

Zenon Szypcio, Katarzyna Dołżyk-Szypcio

引用次数: 0

Compressive and Tensile Strength of Nano-clay Stabilised Soil Subjected to Repeated Freeze–Thaw Cycles 反复冻融循环作用下纳米粘土稳定土的抗压和抗拉强度

IF 0.6

Studia Geotechnica et Mechanica Pub Date : 2023-09-01 DOI: 10.2478/sgem-2023-0009

M. Roustaei, Mahdi Sabetraftar, E. Taherabadi, M. Bayat

{"title":"Compressive and Tensile Strength of Nano-clay Stabilised Soil Subjected to Repeated Freeze–Thaw Cycles","authors":"M. Roustaei, Mahdi Sabetraftar, E. Taherabadi, M. Bayat","doi":"10.2478/sgem-2023-0009","DOIUrl":"https://doi.org/10.2478/sgem-2023-0009","url":null,"abstract":"Abstract Improvement of the mechanical properties of clayey soils by additional elements to enhance the strength under numerous freezing and thawing cycles has been considered as a serious concern for engineering applications in cold regions. The objective of the current study is to investigate the effect of nano-clay as a stabiliser on the mechanical properties of clay. To this end, the clay specimens were prepared by adding various percentages of nano-clay ranging from 0.5% to 3% by dry weight of soil and were experimentally tested under the uniaxial compression and tensile splitting tests under different curing times (0, 7 and 28 days) after experiencing various freeze–thaw cycles ranging from 0 to 11. It can be concluded from the results that nano-clay particles may be used as a stabiliser in geotechnical applications to improve soil property. The results indicate that the optimum moisture content (OMC) of specimens increases and the maximum dry density (MDD) decreases with the increasing nano-clay content. The specimens containing about 1% nano-clay recorded maximum values of unconfined compressive strength (UCS) as well as tensile strength. For example, the addition 1% nano-clay increased the UCS and tensile values of clay specimens under the curing time of 28 days by 34% and 247%, respectively. In addition, the long-term durability of specimens against freeze–thaw cycles increases further with the addition of nano-clay content ranging from 2% to 3%.","PeriodicalId":44626,"journal":{"name":"Studia Geotechnica et Mechanica","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42793595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Shell Deformation During the Construction of Record Span Soil-steel Buried Structure in Ras-Al-Khaimah (UAE) 阿拉伯联合酋长国Ras-Al-Khaimah纪录跨土钢埋地结构施工过程中的壳变形

Studia Geotechnica et Mechanica Pub Date : 2023-09-01 DOI: 10.2478/sgem-2023-0007

Czesław Machelski, Piotr Tomala

引用次数: 0

An elastoplastic constitutive model for assessing ground settlements induced by deep excavations 深基坑地面沉降的弹塑性本构模型

Studia Geotechnica et Mechanica Pub Date : 2023-09-01 DOI: 10.2478/sgem-2023-0011

Hiba El-Arja, Sébastien Burlon, Emmanuel Bourgeois

{"title":"An elastoplastic constitutive model for assessing ground settlements induced by deep excavations","authors":"Hiba El-Arja, Sébastien Burlon, Emmanuel Bourgeois","doi":"10.2478/sgem-2023-0011","DOIUrl":"https://doi.org/10.2478/sgem-2023-0011","url":null,"abstract":"Abstract Ground movements induced by deep excavations may cause damages on neighboring existing buildings. Finite element simulations generally give acceptable estimates of the horizontal displacements of the retaining wall, but results are less satisfactory for the vertical displacements of the ground surface behind the structure. A possible explanation is that most constitutive models describe volumetric strains in a simplified way. This paper proposes an elastoplastic constitutive model aimed at improving the prediction of vertical displacements behind retaining walls. The model comprises a single plastic mechanism with isotropic strain hardening, but has a specific flow rule that allows to generate contractive plastic strains. Identification of the parameters based on triaxial tests is explained and illustrated by an example of calibration. A numerical analysis of a well-documented sheet pile wall in sand in Hochstetten (Germany) is presented. The results given by the model are compared with the measurements and with those obtained using the Hardening Soil Model. The potential advantages of the proposed model are then discussed.","PeriodicalId":44626,"journal":{"name":"Studia Geotechnica et Mechanica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135484322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Vibration monitoring of structures in the light of the Polish and international requirements 根据波兰和国际要求对结构进行振动监测

IF 0.6

Studia Geotechnica et Mechanica Pub Date : 2023-06-27 DOI: 10.2478/sgem-2023-0008

A. Herbut, A. Jakubczyk-Gałczyńska, M. Wyjadłowski

引用次数: 0