Compared with raft foundations, piled raft foundations can effectively reduce settlements caused by external loads such as superstructures, which makes them play an important role in constructions in urban areas. Recently, with the development of new piling methods, steel sheet piles can be penetrated into various types of grounds with high quality and precision. Although piles for piled raft foundations are usually pipe piles, sheet piles could become an alternative because the construction time and cost of sheet piles could be lower than those of pipe piles. Hence, a target of this research is to demonstrate the possibility of using sheet piles for piled raft foundations. In this study, a series of model tests were conducted first to investigate the load transfer behaviours of model piled raft foundations supported by three types of piles in an air-dried sand ground. Two of them were composed of sheet piles, called plate piles, and box pile respectively, and the other was a conventional pipe pile for comparison. Both vertical and horizontal load tests were conducted, and the load sharing between the raft and piles was carefully investigated. Since the plate pile foundation exhibited outstanding behaviours, finite element method (FEM) numerical analyses were then conducted to investigate the foundation-soil interaction in plate pile foundations under vertical and horizontal loading. According to the test and calculated results, a piled raft foundation supported by sheet piles would be a promising alternative to a conventional pipe pile foundation, especially in highly-seismic areas.
{"title":"Vertical and horizontal bearing characteristics of model piled raft foundations supported by sheet piles","authors":"X. Xiong, Wentao Guo, Tatsunori Matsumoto, Yukihiro Ishihara","doi":"10.1680/jphmg.22.00053","DOIUrl":"https://doi.org/10.1680/jphmg.22.00053","url":null,"abstract":"Compared with raft foundations, piled raft foundations can effectively reduce settlements caused by external loads such as superstructures, which makes them play an important role in constructions in urban areas. Recently, with the development of new piling methods, steel sheet piles can be penetrated into various types of grounds with high quality and precision. Although piles for piled raft foundations are usually pipe piles, sheet piles could become an alternative because the construction time and cost of sheet piles could be lower than those of pipe piles. Hence, a target of this research is to demonstrate the possibility of using sheet piles for piled raft foundations. In this study, a series of model tests were conducted first to investigate the load transfer behaviours of model piled raft foundations supported by three types of piles in an air-dried sand ground. Two of them were composed of sheet piles, called plate piles, and box pile respectively, and the other was a conventional pipe pile for comparison. Both vertical and horizontal load tests were conducted, and the load sharing between the raft and piles was carefully investigated. Since the plate pile foundation exhibited outstanding behaviours, finite element method (FEM) numerical analyses were then conducted to investigate the foundation-soil interaction in plate pile foundations under vertical and horizontal loading. According to the test and calculated results, a piled raft foundation supported by sheet piles would be a promising alternative to a conventional pipe pile foundation, especially in highly-seismic areas.","PeriodicalId":48816,"journal":{"name":"International Journal of Physical Modelling in Geotechnics","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43407908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a centrifuge study on the performance of inclined geofoam barriers compared to vertical geofoam barrier for the mitigation of ground vibrations induced by high-speed railways. Three different barrier inclinations (60°, 90° and 120°) are used in three centrifuge models. Each centrifuge model is tested for seven different frequencies. Therefore, the results of 21 centrifuge tests are reported in this paper. The results show that the barrier efficiency of inclined barriers is more than vertical barrier efficiency for the points located behind the barrier. However, for the point located before the barrier, the barrier efficiency reduces by using inclined barriers instead of the vertical barrier. The results also illustrate that the barrier efficiencies for two inclined barriers used in this research, which have supplementary angles, are almost the same.
{"title":"Centrifuge modeling of ground vibrations mitigation by inclined geofoam barrier","authors":"H. Shahnazari, M. Kazemi, M. Baziar","doi":"10.1680/jphmg.22.00032","DOIUrl":"https://doi.org/10.1680/jphmg.22.00032","url":null,"abstract":"This paper presents a centrifuge study on the performance of inclined geofoam barriers compared to vertical geofoam barrier for the mitigation of ground vibrations induced by high-speed railways. Three different barrier inclinations (60°, 90° and 120°) are used in three centrifuge models. Each centrifuge model is tested for seven different frequencies. Therefore, the results of 21 centrifuge tests are reported in this paper. The results show that the barrier efficiency of inclined barriers is more than vertical barrier efficiency for the points located behind the barrier. However, for the point located before the barrier, the barrier efficiency reduces by using inclined barriers instead of the vertical barrier. The results also illustrate that the barrier efficiencies for two inclined barriers used in this research, which have supplementary angles, are almost the same.","PeriodicalId":48816,"journal":{"name":"International Journal of Physical Modelling in Geotechnics","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41763084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Badr Ouzzine, Jean de Sauvage, G. Madabhushi, Giulia M. B. Viggiani, P. Reiffsteck
For several decades, energy piles have been developed to extract heat from the ground by using foundation piles as heat exchangers. However, the thermal loading of these piles directly affects their mechanical behaviour. Centrifuge modelling of a thermally loaded pile group within a groundwater flow makes it possible to improve the understanding of the hydro-thermo-mechanical behaviour of this type of foundation. In this research groundwater flow was established in a centrifuge model to study an energy pile group. The focus of this study is to enhance the research on energy geo-structures such as foundations which are very often located in soil with seepage. The groundwater flow allows reducing the thermomechanical effects and therefore plays the role as a stress and deformation stabiliser in addition to favouring the thermal recharge of the soil.
{"title":"Centrifuge modelling of an energy pile group with ground water flow","authors":"Badr Ouzzine, Jean de Sauvage, G. Madabhushi, Giulia M. B. Viggiani, P. Reiffsteck","doi":"10.1680/jphmg.22.00041","DOIUrl":"https://doi.org/10.1680/jphmg.22.00041","url":null,"abstract":"For several decades, energy piles have been developed to extract heat from the ground by using foundation piles as heat exchangers. However, the thermal loading of these piles directly affects their mechanical behaviour. Centrifuge modelling of a thermally loaded pile group within a groundwater flow makes it possible to improve the understanding of the hydro-thermo-mechanical behaviour of this type of foundation. In this research groundwater flow was established in a centrifuge model to study an energy pile group. The focus of this study is to enhance the research on energy geo-structures such as foundations which are very often located in soil with seepage. The groundwater flow allows reducing the thermomechanical effects and therefore plays the role as a stress and deformation stabiliser in addition to favouring the thermal recharge of the soil.","PeriodicalId":48816,"journal":{"name":"International Journal of Physical Modelling in Geotechnics","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46443118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper describes the methods and outcomes of tests designed to simulate the penetration of a pushed in model pile, or a field testing penetration element. The penetration element was a 25 mm diameter cylinder with a conical tip. The element was advanced into a sand profile subjected to vertical pressure under at-rest conditions. The unique aspect of the testing was the inclusion of in-soil measurement tools. Null soil pressure gages were used to monitor radial pressures and in-soil linear strain devices were used to monitor radial strain at points within a measurement horizon as the penetration element was advanced into the profile. Testing revealed that radial pressures return to their ambient pre-penetration magnitudes once the element passes below a sensing horizon. In-soil radial strain measurements illustrated that the rapid drop in radial soil pressure coincides with a small, but consistent reversal in the increment of radial strain. As distance from the axis of penetration decreases this reversal is more significant. These observations have importance in considering the development of frictional resistance and axial capacity of pushed in piles and at the same time has relevance to the analysis of cone penetration testing in the determination of rational material properties.
{"title":"Measurement of stresses and strains around a pushed in model pile or cone penetrometer","authors":"M. Talesnick, Itamar Omer","doi":"10.1680/jphmg.22.00056","DOIUrl":"https://doi.org/10.1680/jphmg.22.00056","url":null,"abstract":"The paper describes the methods and outcomes of tests designed to simulate the penetration of a pushed in model pile, or a field testing penetration element. The penetration element was a 25 mm diameter cylinder with a conical tip. The element was advanced into a sand profile subjected to vertical pressure under at-rest conditions. The unique aspect of the testing was the inclusion of in-soil measurement tools. Null soil pressure gages were used to monitor radial pressures and in-soil linear strain devices were used to monitor radial strain at points within a measurement horizon as the penetration element was advanced into the profile. Testing revealed that radial pressures return to their ambient pre-penetration magnitudes once the element passes below a sensing horizon. In-soil radial strain measurements illustrated that the rapid drop in radial soil pressure coincides with a small, but consistent reversal in the increment of radial strain. As distance from the axis of penetration decreases this reversal is more significant. These observations have importance in considering the development of frictional resistance and axial capacity of pushed in piles and at the same time has relevance to the analysis of cone penetration testing in the determination of rational material properties.","PeriodicalId":48816,"journal":{"name":"International Journal of Physical Modelling in Geotechnics","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44334496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One of the most significant factors affecting the efficiency of jet grouting operation is the diameter of the constructed column, which depends on soil properties, stress state, and operating parameters, including grout pressure (P), grout flow rate (Q), monitor rotational speed (ω) and lifting step (▵s). Treatment efficiency is to gain a larger diameter with specific energy applied per unit length of the column. In this study, a number of full-scale and small-scale single-fluid jet grouting elements were constructed in the field and laboratory to investigate the effects of the main operating parameters on the diameter and treatment efficiency of the columns constructed in silty sand. Furthermore, measured values and obtained trends were controlled by a comprehensive equation commonly used to predict the diameter of jet grouting columns. Results indicate that an increase in the time interval per step (▵t) and grout pressure (P), as well as a decrease in the lifting step (▵s) causes a larger column diameter and lower treatment efficiency. However, a decline in rotational speed (ω) improve both diameter and efficiency. Subsequently, the well-known equation has been modified by taking into account field measurements in this study to predict more accurate values and trends for both full-scale and small-scale jet grouting elements.
{"title":"Experimental and field investigation to enhance prediction of jet grouting column diameter and efficiency in silty sand","authors":"A. Ghodrati, M. Sabermahani, A. H. Korayem","doi":"10.1680/jphmg.21.00075","DOIUrl":"https://doi.org/10.1680/jphmg.21.00075","url":null,"abstract":"One of the most significant factors affecting the efficiency of jet grouting operation is the diameter of the constructed column, which depends on soil properties, stress state, and operating parameters, including grout pressure (P), grout flow rate (Q), monitor rotational speed (ω) and lifting step (▵s). Treatment efficiency is to gain a larger diameter with specific energy applied per unit length of the column. In this study, a number of full-scale and small-scale single-fluid jet grouting elements were constructed in the field and laboratory to investigate the effects of the main operating parameters on the diameter and treatment efficiency of the columns constructed in silty sand. Furthermore, measured values and obtained trends were controlled by a comprehensive equation commonly used to predict the diameter of jet grouting columns. Results indicate that an increase in the time interval per step (▵t) and grout pressure (P), as well as a decrease in the lifting step (▵s) causes a larger column diameter and lower treatment efficiency. However, a decline in rotational speed (ω) improve both diameter and efficiency. Subsequently, the well-known equation has been modified by taking into account field measurements in this study to predict more accurate values and trends for both full-scale and small-scale jet grouting elements.","PeriodicalId":48816,"journal":{"name":"International Journal of Physical Modelling in Geotechnics","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49619096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geotechnical structures such as levees, dikes, canals and tailing dams, when subjected to extreme climatic conditions, such as flooding and drawdown, are prone to failure on the upstream and downstream sides due to transient seepage conditions. Therefore, it is imperative to physically replicate such conditions in the actual stress state to understand the performance of these geotechnical structures. Hence, the objective of this paper is to present the performance of an in-flight simulator developed to simulate flooding and drawdown (ISFD) events at enhanced gravities. The working principle, design details, various components of the developed simulator, and calibration at normal (1g) and high gravities are discussed. In the present study, the calibration and performance of the ISFD setup were demonstrated on a model levee section in a 4.5 m radius large beam geotechnical centrifuge facility available at the Indian Institute of Technology Bombay, India. The rate of flooding and drawdown varied from 2.2 m/day to 7 m/day and 1.65 m/day to 4.4 m/day (in prototype dimensions), respectively, obtained with the help of pore-water pressure transducers placed on the upstream and downstream sides of the levee section. A total of three centrifuge model tests were conducted on a scaled-down levee section (with and without internal drainage layers) constructed with silty sand type material to validate the ISFD capabilities. In addition, seepage and slope stability analysis for the centrifuge models was carried out using Plaxis-2D geotechnical software which compared favourably with physically observed tests results.
{"title":"Design and development of an in-flight simulator for flooding and drawdown in a geotechnical centrifuge","authors":"B. Viswanadham, R. Saran, Pankaj Kumar","doi":"10.1680/jphmg.21.00093","DOIUrl":"https://doi.org/10.1680/jphmg.21.00093","url":null,"abstract":"Geotechnical structures such as levees, dikes, canals and tailing dams, when subjected to extreme climatic conditions, such as flooding and drawdown, are prone to failure on the upstream and downstream sides due to transient seepage conditions. Therefore, it is imperative to physically replicate such conditions in the actual stress state to understand the performance of these geotechnical structures. Hence, the objective of this paper is to present the performance of an in-flight simulator developed to simulate flooding and drawdown (ISFD) events at enhanced gravities. The working principle, design details, various components of the developed simulator, and calibration at normal (1g) and high gravities are discussed. In the present study, the calibration and performance of the ISFD setup were demonstrated on a model levee section in a 4.5 m radius large beam geotechnical centrifuge facility available at the Indian Institute of Technology Bombay, India. The rate of flooding and drawdown varied from 2.2 m/day to 7 m/day and 1.65 m/day to 4.4 m/day (in prototype dimensions), respectively, obtained with the help of pore-water pressure transducers placed on the upstream and downstream sides of the levee section. A total of three centrifuge model tests were conducted on a scaled-down levee section (with and without internal drainage layers) constructed with silty sand type material to validate the ISFD capabilities. In addition, seepage and slope stability analysis for the centrifuge models was carried out using Plaxis-2D geotechnical software which compared favourably with physically observed tests results.","PeriodicalId":48816,"journal":{"name":"International Journal of Physical Modelling in Geotechnics","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44894234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kazuhiro Hayashi, Shuhei Takahashi, Tomoki Nakamura, S. Tamura
This study aimed to clarify the highly nonlinear behavior of soil–pile system and proposes small-scale reinforced concrete (RC) pile model for use in centrifugal tests. Horizontal static loading centrifugal tests were conducted on 13 small-scale RC pile models at 50-G centrifuge acceleration to illustrate the reproducibility of a full-scale RC pile. The experimental results show that the maximum flexural strength of a small-scale RC pile can be estimated accurately as a function of the full plastic moment Mu. The current design formula for the maximum shear strength Qs in the Architectural Institute of Japan (AIJ) standard is applied to full-scale RC members, while the final fracture mode of the proposed small-scale model corresponds to its estimation. Horizontal static loading centrifugal tests were performed on a soil–pile system consisting of dry sand and a small-scale RC pile model. Furthermore, the experimental results for the soil–pile system correspond well to the ultimate strength based for flexural fracture proposed by Broms (1964) and those for shear fracture according to the AIJ Standard (2010). The experimental results obtained in this study for the proposed small-scale RC pile model are valid for use in assessing a soil–pile system's maximum strength and final fracture mode.
本研究旨在阐明土-桩体系的高度非线性特性，并提出用于离心试验的小尺度钢筋混凝土桩模型。在50-G离心加速度下，对13个小尺寸RC桩模型进行了水平静载离心试验，以说明原尺寸RC桩的可重复性。试验结果表明，小尺度钢筋混凝土桩的最大抗弯强度可以准确地估计为全塑性弯矩Mu的函数。现行日本建筑学会(Architectural Institute of Japan, AIJ)标准中最大抗剪强度Qs的设计公式适用于全尺寸RC构件，而所提出的小尺寸模型的最终断裂模式与其估算值相对应。在由干砂和小尺度钢筋混凝土桩模型组成的土-桩体系上进行了水平静荷载离心试验。此外，土桩体系的试验结果与Broms(1964)提出的基于弯曲断裂的极限强度和AIJ标准(2010)提出的基于剪切断裂的极限强度相吻合。本文提出的小尺度钢筋混凝土桩模型的试验结果可用于评估土桩体系的最大强度和最终断裂模式。
{"title":"Centrifuge testing of nonlinear soil–pile response using 1:50 scale reinforced concrete pile models","authors":"Kazuhiro Hayashi, Shuhei Takahashi, Tomoki Nakamura, S. Tamura","doi":"10.1680/jphmg.22.00049","DOIUrl":"https://doi.org/10.1680/jphmg.22.00049","url":null,"abstract":"This study aimed to clarify the highly nonlinear behavior of soil–pile system and proposes small-scale reinforced concrete (RC) pile model for use in centrifugal tests. Horizontal static loading centrifugal tests were conducted on 13 small-scale RC pile models at 50-G centrifuge acceleration to illustrate the reproducibility of a full-scale RC pile. The experimental results show that the maximum flexural strength of a small-scale RC pile can be estimated accurately as a function of the full plastic moment Mu. The current design formula for the maximum shear strength Qs in the Architectural Institute of Japan (AIJ) standard is applied to full-scale RC members, while the final fracture mode of the proposed small-scale model corresponds to its estimation. Horizontal static loading centrifugal tests were performed on a soil–pile system consisting of dry sand and a small-scale RC pile model. Furthermore, the experimental results for the soil–pile system correspond well to the ultimate strength based for flexural fracture proposed by Broms (1964) and those for shear fracture according to the AIJ Standard (2010). The experimental results obtained in this study for the proposed small-scale RC pile model are valid for use in assessing a soil–pile system's maximum strength and final fracture mode.","PeriodicalId":48816,"journal":{"name":"International Journal of Physical Modelling in Geotechnics","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45294574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1680/jphmg.2023.23.1.1
Xianfeng Ma
{"title":"Editorial","authors":"Xianfeng Ma","doi":"10.1680/jphmg.2023.23.1.1","DOIUrl":"https://doi.org/10.1680/jphmg.2023.23.1.1","url":null,"abstract":"","PeriodicalId":48816,"journal":{"name":"International Journal of Physical Modelling in Geotechnics","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45997370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tianqiang Jia, S. Stanier, P. Watson, Xiaowei Feng, S. Gourvenec
Tolerably mobile subsea foundations may be used to replace conventional fixed mudmat foundations for pipeline infrastructure and are designed to slide on the seabed along with the connected pipeline, in order to accommodate thermally induced horizontal forces. This allows the size of the foundation and the resulting fabrication and installation costs to be substantially reduced. The performance of mobile foundations is explored in this paper through four centrifuge model tests on a NC or LOC reconstituted calcareous silt obtained from the Northwest Shelf of Western Australia. The results are compared to three existing tests performed on a kaolin clay. The results show that under typical periodic surface sliding and intervening rests, sliding resistance evolves within a cycle with resistance peaks evident at either end of the sliding footprint due to the formation of berms, and the residual resistance increasing with sliding cycles towards a drained state. Shear and consolidation induced settlements accumulate with sliding cycles although at a reducing rate. The tests in the calcareous silt show higher normalised initial peak sliding resistance, a more dramatic loss and slower recovery of sliding resistance with cycles, and slower rate of decrease of incremental settlement compared with the response in kaolin clay.
{"title":"Centrifuge testing of a tolerably mobile subsea foundation: exploring the effect of soil type on the evolution of whole-life resistance and settlement","authors":"Tianqiang Jia, S. Stanier, P. Watson, Xiaowei Feng, S. Gourvenec","doi":"10.1680/jphmg.22.00017","DOIUrl":"https://doi.org/10.1680/jphmg.22.00017","url":null,"abstract":"Tolerably mobile subsea foundations may be used to replace conventional fixed mudmat foundations for pipeline infrastructure and are designed to slide on the seabed along with the connected pipeline, in order to accommodate thermally induced horizontal forces. This allows the size of the foundation and the resulting fabrication and installation costs to be substantially reduced. The performance of mobile foundations is explored in this paper through four centrifuge model tests on a NC or LOC reconstituted calcareous silt obtained from the Northwest Shelf of Western Australia. The results are compared to three existing tests performed on a kaolin clay. The results show that under typical periodic surface sliding and intervening rests, sliding resistance evolves within a cycle with resistance peaks evident at either end of the sliding footprint due to the formation of berms, and the residual resistance increasing with sliding cycles towards a drained state. Shear and consolidation induced settlements accumulate with sliding cycles although at a reducing rate. The tests in the calcareous silt show higher normalised initial peak sliding resistance, a more dramatic loss and slower recovery of sliding resistance with cycles, and slower rate of decrease of incremental settlement compared with the response in kaolin clay.","PeriodicalId":48816,"journal":{"name":"International Journal of Physical Modelling in Geotechnics","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44931951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. S. Domingos, C. Pinto, F. Danziger, Arthur V. S. Pinheiro, T. Lunne
Large flexible calibration chambers (CC) to evaluate and develop interpretation methods for cone penetration tests (CPT) in cohesionless soils have been used since the late 1960s. Nevertheless, only average boundary stress values are known in almost all tests already performed. Tactile Pressure Sensors represent a useful tool to assess the stress distribution in an area under loading and have been applied in some geotechnical studies. The present study presents the results of CPTs carried out on a large flexible CC in a very loose and a medium dense fine quartz sand. Tactile pressure sensors were placed on the walls of the CC, allowing the measurement of horizontal stresses and their spatial distribution in all test phases: sample formation, lateral and cavity cell filling, piston filling, sample stressing, and CPT. In particular, the Tactile Pressure Sensors were able to measure the horizontal stresses before the cavity and lateral cell filling, i.e. when no information is available about the horizontal stresses in regular tests. The measurements contribute to the discussion on the influence of the CC boundaries on the test results. The results encourage the use of tactile pressure sensors in a more routinely base in large flexible CC testing.
{"title":"The use of tactile pressure sensors for horizontal stress measurements on a large flexible Calibration Chamber","authors":"G. S. Domingos, C. Pinto, F. Danziger, Arthur V. S. Pinheiro, T. Lunne","doi":"10.1680/jphmg.21.00084","DOIUrl":"https://doi.org/10.1680/jphmg.21.00084","url":null,"abstract":"Large flexible calibration chambers (CC) to evaluate and develop interpretation methods for cone penetration tests (CPT) in cohesionless soils have been used since the late 1960s. Nevertheless, only average boundary stress values are known in almost all tests already performed. Tactile Pressure Sensors represent a useful tool to assess the stress distribution in an area under loading and have been applied in some geotechnical studies. The present study presents the results of CPTs carried out on a large flexible CC in a very loose and a medium dense fine quartz sand. Tactile pressure sensors were placed on the walls of the CC, allowing the measurement of horizontal stresses and their spatial distribution in all test phases: sample formation, lateral and cavity cell filling, piston filling, sample stressing, and CPT. In particular, the Tactile Pressure Sensors were able to measure the horizontal stresses before the cavity and lateral cell filling, i.e. when no information is available about the horizontal stresses in regular tests. The measurements contribute to the discussion on the influence of the CC boundaries on the test results. The results encourage the use of tactile pressure sensors in a more routinely base in large flexible CC testing.","PeriodicalId":48816,"journal":{"name":"International Journal of Physical Modelling in Geotechnics","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2022-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48254180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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