Pub Date : 2005-07-01DOI: 10.1680/GENG.2005.158.3.169
G. Lei
In geotechnical engineering, stability of the openings formed by excavation is of much concern in controlling the design feasibility and construction workability of underground structures. Analysis of the stability of the excavated openings and the corresponding measures against instability inevitably necessitate a good understanding of the yielding and failure mechanisms of the openings. This paper proposes a mechanism of potential yielding across an excavated rectangular diaphragm wall panel trench. By using an elastic analytical solution to the problem of horizontal stress changes and displacements induced during the installation of a rectangular diaphragm wall panel, two extreme cases (panel trenches with dimensions 1 m × 1 m and 6 m × 1 m) have been analysed to investigate the distribution of the principal stress change of the soils around the trenches due to excavation. It has been found that, when the elastic limit is reached, soils with different consolidation histories will exhibit different yiel...
在岩土工程中，开挖形成的孔洞的稳定性是控制地下结构设计可行性和施工可行性的重要因素。分析开挖孔洞的稳定性及相应的抗失稳措施，必然需要对孔洞的屈服和破坏机制有较好的认识。本文提出了开挖的矩形连续墙板沟槽的潜在屈服机理。采用矩形连续墙板安装过程中引起的水平应力变化和位移问题的弹性解析解，分析了两种极端情况(1 m × 1 m和6 m × 1 m的板沟)，探讨了开挖引起的槽周围土体主应力变化的分布。研究发现，当达到弹性极限时，不同固结历史的土表现出不同的屈服特性。
{"title":"Yielding mechanisms in a rectangular trench","authors":"G. Lei","doi":"10.1680/GENG.2005.158.3.169","DOIUrl":"https://doi.org/10.1680/GENG.2005.158.3.169","url":null,"abstract":"In geotechnical engineering, stability of the openings formed by excavation is of much concern in controlling the design feasibility and construction workability of underground structures. Analysis of the stability of the excavated openings and the corresponding measures against instability inevitably necessitate a good understanding of the yielding and failure mechanisms of the openings. This paper proposes a mechanism of potential yielding across an excavated rectangular diaphragm wall panel trench. By using an elastic analytical solution to the problem of horizontal stress changes and displacements induced during the installation of a rectangular diaphragm wall panel, two extreme cases (panel trenches with dimensions 1 m × 1 m and 6 m × 1 m) have been analysed to investigate the distribution of the principal stress change of the soils around the trenches due to excavation. It has been found that, when the elastic limit is reached, soils with different consolidation histories will exhibit different yiel...","PeriodicalId":45150,"journal":{"name":"Geotechnical Engineering","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1680/GENG.2005.158.3.169","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67402367","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}
Pub Date : 2005-07-01DOI: 10.1680/GENG.2005.158.3.159
A. Hunter
Impact moles and directional drilling units form tunnels of up to approximately 300 mm in diameter at a depth of 1–2 m. They are typically used for the installation of electricity cables or small-diameter pipelines. This type of tunnelling differs from conventional tunnelling owing to the lack of soil excavation. The tunnel is formed by dynamically expelling soil outwards in a predominantly radial direction. This creates a stress and displacement field that has the potential to damage existing services and buildings. To reduce the risk of damage to existing structures installation guidelines detailing acceptable proximity distances need to be provided. This paper details a methodology that has been used to calculate acceptable proximity distances to existing grey iron pipelines that have a transverse geometric configuration to the new pipeline. The study utilises finite difference techniques in conjunction with analytical cavity expansion solutions to determine the stress–strain field induced by tunnellin...
{"title":"Effect of trenchless technologies on existing iron pipelines","authors":"A. Hunter","doi":"10.1680/GENG.2005.158.3.159","DOIUrl":"https://doi.org/10.1680/GENG.2005.158.3.159","url":null,"abstract":"Impact moles and directional drilling units form tunnels of up to approximately 300 mm in diameter at a depth of 1–2 m. They are typically used for the installation of electricity cables or small-diameter pipelines. This type of tunnelling differs from conventional tunnelling owing to the lack of soil excavation. The tunnel is formed by dynamically expelling soil outwards in a predominantly radial direction. This creates a stress and displacement field that has the potential to damage existing services and buildings. To reduce the risk of damage to existing structures installation guidelines detailing acceptable proximity distances need to be provided. This paper details a methodology that has been used to calculate acceptable proximity distances to existing grey iron pipelines that have a transverse geometric configuration to the new pipeline. The study utilises finite difference techniques in conjunction with analytical cavity expansion solutions to determine the stress–strain field induced by tunnellin...","PeriodicalId":45150,"journal":{"name":"Geotechnical Engineering","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1680/GENG.2005.158.3.159","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67402360","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}
Pub Date : 2005-04-01DOI: 10.1680/GENG.2005.158.2.107
W. Lim, G. McDowell, A. Collop
It is important to be able to distinguish easily between ballasts of poor quality and good quality in terms of strength. For a range of uniformly graded granular materials compacted to the same relative density, there will be two important factors influencing the strength of the aggregate: particle strength and voids ratio (which will be a function of particle shape). Large oedometer tests have been performed in addition to box tests and single particle crushing tests and a new parameter, called the relative strength index, is defined to incorporate the effects of both particle strength and voids ratio. It is found that the relative strength index correlates well with the amount of degradation of ballast in both the large oedometer tests and the box tests, and therefore shows promise as a suitable method for comparing ballast types without having to apply thousands of cycles of load on each ballast.
{"title":"Quantifying the relative strengths of railway ballasts","authors":"W. Lim, G. McDowell, A. Collop","doi":"10.1680/GENG.2005.158.2.107","DOIUrl":"https://doi.org/10.1680/GENG.2005.158.2.107","url":null,"abstract":"It is important to be able to distinguish easily between ballasts of poor quality and good quality in terms of strength. For a range of uniformly graded granular materials compacted to the same relative density, there will be two important factors influencing the strength of the aggregate: particle strength and voids ratio (which will be a function of particle shape). Large oedometer tests have been performed in addition to box tests and single particle crushing tests and a new parameter, called the relative strength index, is defined to incorporate the effects of both particle strength and voids ratio. It is found that the relative strength index correlates well with the amount of degradation of ballast in both the large oedometer tests and the box tests, and therefore shows promise as a suitable method for comparing ballast types without having to apply thousands of cycles of load on each ballast.","PeriodicalId":45150,"journal":{"name":"Geotechnical Engineering","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1680/GENG.2005.158.2.107","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67402183","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}
Pub Date : 2005-04-01DOI: 10.1680/GENG.2005.158.2.63
Dora C.N. Nip, C. Ng
Field lateral load tests were conducted on two single 1·5 m diameter large bored piles in Hong Kong. The test piles are embedded in superficial deposits and weathered rocks with various degrees of decomposition. In this paper, the pile load test results are interpreted and reported. A simple and rational method of back-analysis for long piles, using inclinometer data and assuming a fourth-order polynomial to represent the shape of soil reaction profile, is introduced. The method, requiring only simple spreadsheet-type operations, makes it possible to incorporate non-linear concrete behaviour in the back-analysis, and to deduce the p–y curves for future design of piles in similar ground conditions. In order to verify the rational method, an analysis is carried out using the back-analysed p–y curves, and the predictions are found to agree well with the measured pile head deflections. This proposed method demonstrates how p–y curves are back-analysed rationally for long piles embedded in complex ground condi...
{"title":"Back-analysis of laterally loaded bored piles","authors":"Dora C.N. Nip, C. Ng","doi":"10.1680/GENG.2005.158.2.63","DOIUrl":"https://doi.org/10.1680/GENG.2005.158.2.63","url":null,"abstract":"Field lateral load tests were conducted on two single 1·5 m diameter large bored piles in Hong Kong. The test piles are embedded in superficial deposits and weathered rocks with various degrees of decomposition. In this paper, the pile load test results are interpreted and reported. A simple and rational method of back-analysis for long piles, using inclinometer data and assuming a fourth-order polynomial to represent the shape of soil reaction profile, is introduced. The method, requiring only simple spreadsheet-type operations, makes it possible to incorporate non-linear concrete behaviour in the back-analysis, and to deduce the p–y curves for future design of piles in similar ground conditions. In order to verify the rational method, an analysis is carried out using the back-analysed p–y curves, and the predictions are found to agree well with the measured pile head deflections. This proposed method demonstrates how p–y curves are back-analysed rationally for long piles embedded in complex ground condi...","PeriodicalId":45150,"journal":{"name":"Geotechnical Engineering","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1680/GENG.2005.158.2.63","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67402240","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}
Pub Date : 2005-04-01DOI: 10.1680/GENG.158.2.95.61626
D. Chapman, C. Rogers, Pcf Ng
Pipe splitting is used for the on-line replacement of pipelines made from ductile materials, for example ductile iron and steel. It is a relatively new technique, and so there is limited knowledge ...
管道劈裂用于在线更换由球墨铸铁和球墨钢等球墨材料制成的管道。这是一种相对较新的技术，所以知识有限。
{"title":"Predicting ground displacements caused by pipe-splitting","authors":"D. Chapman, C. Rogers, Pcf Ng","doi":"10.1680/GENG.158.2.95.61626","DOIUrl":"https://doi.org/10.1680/GENG.158.2.95.61626","url":null,"abstract":"Pipe splitting is used for the on-line replacement of pipelines made from ductile materials, for example ductile iron and steel. It is a relatively new technique, and so there is limited knowledge ...","PeriodicalId":45150,"journal":{"name":"Geotechnical Engineering","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67401312","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}
Pub Date : 2005-04-01DOI: 10.1680/GENG.2005.158.2.113
K. Kyrou, A. Penman, C. Artemis
The 74 m high Lefkara embankment dam was built in the early 1970s for the Republic of Cyprus Water Development Department in order to supply domestic water to the cities of Famagusta and Larnaca. I...
{"title":"The first 30 years of Lefkara Dam","authors":"K. Kyrou, A. Penman, C. Artemis","doi":"10.1680/GENG.2005.158.2.113","DOIUrl":"https://doi.org/10.1680/GENG.2005.158.2.113","url":null,"abstract":"The 74 m high Lefkara embankment dam was built in the early 1970s for the Republic of Cyprus Water Development Department in order to supply domestic water to the cities of Famagusta and Larnaca. I...","PeriodicalId":45150,"journal":{"name":"Geotechnical Engineering","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1680/GENG.2005.158.2.113","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67402193","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}
Pub Date : 2005-04-01DOI: 10.1680/GENG.2005.158.2.75
G. Houlsby, B. Byrne
Suction-installed skirted foundations, often referred to as suction caissons, are increasingly being used for a variety of offshore applications. In designing a caisson a geotechnical engineer must consider the installation process as well as the in-place performance. The purpose of this paper is to present calculation procedures for the installation of a caisson in clay. For clay sites, the caisson will often be used as an anchor, with the ratio of the skirt length (L) to the diameter (D) as high as 5. Calculation methods are presented for determining the resistance to penetration of open-ended cylindrical caisson foundations with and without the application of suction inside the caisson. Comparisons between predictions and case records are made. A companion paper describes the calculation procedure for installation in sand soils. Finally, comments are made here about installation in a variety of soils other than homogeneous deposits of clay or sand.
{"title":"Design procedures for installation of suction caissons in clay and other materials","authors":"G. Houlsby, B. Byrne","doi":"10.1680/GENG.2005.158.2.75","DOIUrl":"https://doi.org/10.1680/GENG.2005.158.2.75","url":null,"abstract":"Suction-installed skirted foundations, often referred to as suction caissons, are increasingly being used for a variety of offshore applications. In designing a caisson a geotechnical engineer must consider the installation process as well as the in-place performance. The purpose of this paper is to present calculation procedures for the installation of a caisson in clay. For clay sites, the caisson will often be used as an anchor, with the ratio of the skirt length (L) to the diameter (D) as high as 5. Calculation methods are presented for determining the resistance to penetration of open-ended cylindrical caisson foundations with and without the application of suction inside the caisson. Comparisons between predictions and case records are made. A companion paper describes the calculation procedure for installation in sand soils. Finally, comments are made here about installation in a variety of soils other than homogeneous deposits of clay or sand.","PeriodicalId":45150,"journal":{"name":"Geotechnical Engineering","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1680/GENG.2005.158.2.75","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67402250","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}
Pub Date : 2005-04-01DOI: 10.1680/GENG.2005.158.2.83
M. Mavroulidou, M. Gunn, R. Woods
Engineers need versatile tools in order to design successful dewatering schemes to counteract the effects of changing groundwater levels in cities. In the present paper, a finite-element program is used to perform pumping analyses, involving moving phreatic surfaces and possible desaturation of materials. First, a problem of local dewatering from a line of wells is analysed, involving desaturation of the soil. The results from an analytical solution as well as those of the numerical model are compared with field data. It is shown that the numerical results, accounting for soil desaturation, are closer to field measurements. Second, the ability of the finite-element program to model falling and subsequently rising groundwater levels in cities due to variable water abstraction (as in the case of London) is assessed. The techniques show promise and are sufficiently flexible to be applied to other geologies and boundary conditions.
{"title":"Numerical modelling of groundwater pumping processes","authors":"M. Mavroulidou, M. Gunn, R. Woods","doi":"10.1680/GENG.2005.158.2.83","DOIUrl":"https://doi.org/10.1680/GENG.2005.158.2.83","url":null,"abstract":"Engineers need versatile tools in order to design successful dewatering schemes to counteract the effects of changing groundwater levels in cities. In the present paper, a finite-element program is used to perform pumping analyses, involving moving phreatic surfaces and possible desaturation of materials. First, a problem of local dewatering from a line of wells is analysed, involving desaturation of the soil. The results from an analytical solution as well as those of the numerical model are compared with field data. It is shown that the numerical results, accounting for soil desaturation, are closer to field measurements. Second, the ability of the finite-element program to model falling and subsequently rising groundwater levels in cities due to variable water abstraction (as in the case of London) is assessed. The techniques show promise and are sufficiently flexible to be applied to other geologies and boundary conditions.","PeriodicalId":45150,"journal":{"name":"Geotechnical Engineering","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1680/GENG.2005.158.2.83","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67402278","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}
Pub Date : 2005-01-01DOI: 10.1680/GENG.2005.158.1.35
R. Berardi, R. Bovolenta
Understanding the principal features of soil stiffness has been one of the major achievements of geotechnical engineering over the past 30 years. The study of modulus degradation is now one of the main research areas. Understanding non-linearity is essential in foundation design for accurate and reliable evaluation of ground movements. This paper looks at the problem of assessing of deep foundation settlements and describes two approaches developed to enable designers to take soil–foundation non-linear behaviour into account. The first provides in-field stiffness parameters evaluated by back-analysis of full-scale piles. The second involves deducting the behaviour of the soil interacting with a foundation from degradation curves characterising the soil stiffness.
{"title":"Pile-settlement evaluation using field stiffness non-linearity","authors":"R. Berardi, R. Bovolenta","doi":"10.1680/GENG.2005.158.1.35","DOIUrl":"https://doi.org/10.1680/GENG.2005.158.1.35","url":null,"abstract":"Understanding the principal features of soil stiffness has been one of the major achievements of geotechnical engineering over the past 30 years. The study of modulus degradation is now one of the main research areas. Understanding non-linearity is essential in foundation design for accurate and reliable evaluation of ground movements. This paper looks at the problem of assessing of deep foundation settlements and describes two approaches developed to enable designers to take soil–foundation non-linear behaviour into account. The first provides in-field stiffness parameters evaluated by back-analysis of full-scale piles. The second involves deducting the behaviour of the soil interacting with a foundation from degradation curves characterising the soil stiffness.","PeriodicalId":45150,"journal":{"name":"Geotechnical Engineering","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2005-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1680/GENG.2005.158.1.35","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67402126","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}
Pub Date : 2005-01-01DOI: 10.1680/GENG.2005.158.1.45
K. Hau, G. McDowell
In the design of a pavement, the permissible rut depth and permissible resilient vertical strain at the top of the subgrade at the end of the construction stage (i.e. before the placing of the bituminous layer) are used to select the appropriate thickness of granular material. However, usually the only available data for the subgrade is the resilient modulus, which is estimated from the California Bearing Ratio. This paper examines the application of a new three-surface kinematic hardening model for the subgrade in a finite-element analysis to evaluate the rut depth and resilient vertical strain at the top of the subgrade at the end of the construction stage. The resilient modulus for the subgrade is determined by examining the stress changes at different depths in the subgrade, for different thicknesses of granular material, and applying such stress changes to simulated triaxial samples for 50 cycles to compute the resilient modulus at different depths for input to a layered elastic analysis, in order to...
{"title":"Evaluating permissible subgrade rut depth in pavement design","authors":"K. Hau, G. McDowell","doi":"10.1680/GENG.2005.158.1.45","DOIUrl":"https://doi.org/10.1680/GENG.2005.158.1.45","url":null,"abstract":"In the design of a pavement, the permissible rut depth and permissible resilient vertical strain at the top of the subgrade at the end of the construction stage (i.e. before the placing of the bituminous layer) are used to select the appropriate thickness of granular material. However, usually the only available data for the subgrade is the resilient modulus, which is estimated from the California Bearing Ratio. This paper examines the application of a new three-surface kinematic hardening model for the subgrade in a finite-element analysis to evaluate the rut depth and resilient vertical strain at the top of the subgrade at the end of the construction stage. The resilient modulus for the subgrade is determined by examining the stress changes at different depths in the subgrade, for different thicknesses of granular material, and applying such stress changes to simulated triaxial samples for 50 cycles to compute the resilient modulus at different depths for input to a layered elastic analysis, in order to...","PeriodicalId":45150,"journal":{"name":"Geotechnical Engineering","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2005-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1680/GENG.2005.158.1.45","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67402176","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}
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