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1 – 10 of over 71000Junru Zhang, Yumeng Liu and Bo Yan
This study aims to research the large cross-section tunnel stability evaluation method corrected after considering the thickness-span ratio.
Abstract
Purpose
This study aims to research the large cross-section tunnel stability evaluation method corrected after considering the thickness-span ratio.
Design/methodology/approach
First, taking the Liuyuan Tunnel of Huanggang-Huangmei High-Speed Railway as an example and taking deflection of the third principal stress of the surrounding rock at a vault after tunnel excavation as the criterion, the critical buried depth of the large section tunnel was determined. Then, the strength reduction method was employed to calculate the tunnel safety factor under different rock classes and thickness-span ratios, and mathematical statistics was conducted to identify the relationships of the tunnel safety factor with the thickness-span ratio and the basic quality (BQ) index of the rock for different rock classes. Finally, the influences of thickness-span ratio, groundwater, initial stress of rock and structural attitude factors were considered to obtain the corrected BQ, based on which the stability of a large cross-section tunnel with a depth of more than 100 m during mechanized operation was analyzed. This evaluation method was then applied to Liuyuan Tunnel and Cimushan No. 2 Tunnel of Chongqing Urban Expressway for verification.
Findings
This study shows that under different rock classes, the tunnel safety factor is a strict power function of the thickness-span ratio, while a linear function of the BQ to some extent. It is more suitable to use the corrected BQ as a quantitative index to evaluate tunnel stability according to the actual conditions of the site.
Originality/value
The existing industry standards do not consider the influence of buried depth and span in the evaluation of tunnel stability. The stability evaluation method of large section tunnel considering the correction of overburden span ratio proposed in this paper achieves higher accuracy for the stability evaluation of surrounding rock in a full or large-section mechanized excavation of double line high-speed railway tunnels.
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Hawraa Alateya and Alireza Ahangar Asr
This study is an attempt to estimate the influence of the presence of cavities on the stability of slopes in earth dams under rapid drawdown conditions. The purpose of this paper…
Abstract
Purpose
This study is an attempt to estimate the influence of the presence of cavities on the stability of slopes in earth dams under rapid drawdown conditions. The purpose of this paper is to study the influence of different factors, such as the diameter and location of cavities, in addition to their existence effects.
Design/methodology/approach
A series of finite element simulation models were developed using PLAXIS 2D finite element software to analyse the stability of slopes in earth dams while considering various effects from cavities in the subsoil under rapid drawdown conditions.
Findings
The results indicated that the presence of cavities and an increase in the diameter of cavities decreased the stability of the upstream face dramatically for all examined locations in a horizontal direction; however, this effect was less on the downstream side. The results also showed that variations in the location of cavities in the horizontal direction have a greater effect on the stability than those in the vertical direction. The results revealed that increasing shear strength parameters of embankment does not reduce the influence of cavities on stability when those cavities are in critical locations.
Originality/value
A numerical model has been developed to simulate the effects of cavities on the stability of slopes in water-retaining structures/earth dams. The stability of earth dam slopes on upstream and downstream sides under rapid drawdown conditions considering various cavity effects, including their existence, diameter and location, were numerically analysed.
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Monica Malhotra, Vaishali Sahu, Amit Srivastava and Anil Kumar Misra
The purpose of this study is to investigate the effect of presence of buried flexible pipe on the bearing capacity of shallow footing. First, a model study is performed where…
Abstract
Purpose
The purpose of this study is to investigate the effect of presence of buried flexible pipe on the bearing capacity of shallow footing. First, a model study is performed where shallow footing model is tested for its load settlement behavior, with and without the existence of buried PVC pipe lying vertically below the base of the footing.
Design/methodology/approach
The experimental set-up consisted of a steel box filled with sand at two different relative density values [RD = 50 per cent (medium dense) and RD = 80 per cent (dense sand)] and vertical load was applied on the model footing through hydraulic jack and reaction frame arrangement connected with a proving ring. Test results are verified numerically using commercially available finite element code PLAXIS 2D. With due verification, a parametric study has been conducted, numerically, by varying the range of input parameters, such as unit weight, angle of internal friction, diameter of buried conduit and the Elastic modulus of the soil to assess the pre cent reduction in the capacity of the foundation soil because of the presence of underlying buried flexible pipe.
Findings
Results show that for each footing, there exists a critical depth below which the presence of the buried conduit has negligible influence on the footing performance. When the conduit is located above the critical depth, the bearing capacity of the footing varies with various factors, such as geotechnical parameters of soil and location and diameter of the buried conduit.
Originality/value
It is an original paper performed to assess the presence of buried flexible pipe on the bearing capacity of the shallow footing.
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Annie Liu, Mark Leach and Richa Chugh
The purpose of this study is to develop a sales process framework to facilitate business-to-business (B2B) customer reacquisition. A comprehensive CRM process needs to include…
Abstract
Purpose
The purpose of this study is to develop a sales process framework to facilitate business-to-business (B2B) customer reacquisition. A comprehensive CRM process needs to include reacquisition strategies. Yet, very few firms have formal procedures to guide reacquisition efforts. This gap in the sales process reflects the relatively sparse literature on B2B customer reacquisition models. The present research intends to fill this gap and creates a sales process model to guide salespeople to regain B2B lost customers.
Design/methodology/approach
Using critical incident technique (CIT), this study conducted in-depth interviews with 54 B2B salespeople. Each salesperson reported one successful and one unsuccessful reacquisition incidents. A total of 108 critical incidents were collected for analysis.
Findings
A four-step sales process model to regain B2B customers was developed and empirically supported, including: Segment lost customers; Assess reasons for loss; Develop reacquisition activities; and Implement reacquisition strategies.
Research limitations/implications
This study is qualitative and exploratory in nature; future research should develop dyadic surveys to validate the results.
Practical implications
This four-step reacquisition process allows sales firms to identify essential elements and establish protocols/policies to train and motivate salespeople. The framework can facilitate salespeople develop problem-focused solutions to correctly diagnose the situation and effectively re-negotiate with defected customers. Thus, this process may help reduce inefficiency in the reacquisition process and increase reacquisition ratios.
Social implications
By considering justice/fairness from customer’s perspective, sales firm may properly recover lost business relationship, and do so in ways that are considered both just and ethical.
Originality/value
This is one of the first studies to examine the reacquisition of lost B2B customers. It expands on the traditional sales process to include four steps that enable a sales reacquisition process.
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Mehrdad Rahmani, Aynaz Lotfata, Sarasadat Khoshnevis, Komar Javanmardi and Mehmet Emin Akdogan
Tehran’s health-care system is growing, yet it lacks emergency planning procedures. The premise of this study is that the urban environment around a hospital is just as robust as…
Abstract
Purpose
Tehran’s health-care system is growing, yet it lacks emergency planning procedures. The premise of this study is that the urban environment around a hospital is just as robust as the hospital itself. This study aims to look at hospital resilience in an urban setting to see where it may be improved to keep the hospital operational during a disaster.
Design/methodology/approach
The urban resilience (UR) of Amir-Alam Hospital was analyzed in this study using a customized version of the United Nations Office for Disaster Risk Reduction’s City Resilience Profiling Tool. The 34 indications were broken down into five categories.
Findings
The result revealed that the hospital’s UR score was 51.75 out of 100, indicating medium resilience. The results of this study enable the decision-makers to determine what measures they may take to improve the hospital’s resilience in terms of its surrounding urban context.
Originality/value
The originality of this research is based on the surrounding urban environment’s resilience as an integral part of hospital resilience.
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Xiao‐Jun Yan, Hao‐Yue Li and Jing‐Xu Nie
Inclusions have been shown to be the most significant factor to decrease the low cycle fatigue (LCF) life in powder metallurgy (PM) alloys used by most of turbine discs for…
Abstract
Inclusions have been shown to be the most significant factor to decrease the low cycle fatigue (LCF) life in powder metallurgy (PM) alloys used by most of turbine discs for advanced turboengines. In this paper, effects of inclusions on PM alloys' LCF life are evaluated through the definition of initial damage value D0 based on damage mechanics. By investigating the relationship between D0 and characteristic dimension of inclusions, Bussac's probabilistic model is extended to consider surface and internal inclusions together.
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Yunlong Jiao, Xiaojun Liu and Kun Liu
Driving safety on a wet road is closely related to the wet skid resistance of tires. The purpose of this paper is to reveal the evolution of wet skid resistance at different water…
Abstract
Purpose
Driving safety on a wet road is closely related to the wet skid resistance of tires. The purpose of this paper is to reveal the evolution of wet skid resistance at different water film thicknesses and provide some guidance on the design of a tread pattern with improved traction on rainy roads.
Design/methodology/approach
Brake tests are performed in a laboratory with a viscoelastic tribotester at various water film thicknesses. The initial water film thickness is 3 mm, which decreases with an increase in the test number. Brake friction force is dynamically measured at water film thicknesses ranging from 0 mm to 3 mm.
Findings
The results show that water film thickness exerts a great influence on the forms of tire motion and slip ratio. The tire is much easier to slide on the road with thick water film and also with a considerably thin water film (about 0-1 mm) during a sharp braking process. The brake traction can be very low under this road condition despite the apparently safe quality of the road.
Originality/value
The authors design and establish a new viscoelastic tribotester which is used to simulate the real braking sliding process and study the tribological properties between tire rubber and road surface. The variation in the wet friction coefficient and slip ratio at different water film thicknesses have a great influence on the design of a tread pattern with improved traction on rainy roads.
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This paper aims to analyse normative corporate governance evolution in the UK between 1995 and 2014 against the benchmark of Organisation for Economic Co-Operation and Development…
Abstract
Purpose
This paper aims to analyse normative corporate governance evolution in the UK between 1995 and 2014 against the benchmark of Organisation for Economic Co-Operation and Development (OECD) regulatory principles.
Design/methodology/approach
Methodologically, the authors conduct an empirical, longitudinal data set analysis of the formative years of UK normative corporate governance development between 1995 and 2014. We provide a qualitative discussion of the empirical evidence that links the type of UK regulatory corporate governance development to financial market growth thereby adopting a mixed approach based on quantitative and qualitative research methods.
Findings
The authors find that compared to the OECD model of corporate governance, the UK model is less rigid following a more self-regulatory approach based upon a “comply or explain” paradigm. Thus it is scored below corporate governance systems that follow a compulsory implementation model. However, even with such “low” tilt towards formal shareholder primacy norms, the UK has the best performing financial market. As a quasi-empirical study, the authors suggest that there are several historical and economic reasons for this, which together with a robust rule of law in the UK contribute to this performance – and the law especially the type or tilt is less relevant.
Originality/value
This is the first of its kind empirical, longitudinal data set analysis with qualitative elements that links empirical evidence to regulatory developments in the wider context of UK corporate governance evolution.
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María José Mayorga Fernández, Noemí Peña Trapero and Lourdes De La Rosa Moreno
This paper focuses on analysis of the incorporation of a Lesson Study cycle within the university training proposal, as a teaching strategy in initial training in the Infant…
Abstract
Purpose
This paper focuses on analysis of the incorporation of a Lesson Study cycle within the university training proposal, as a teaching strategy in initial training in the Infant Education Degree.
Design/methodology/approach
Qualitative research was conducted through a case study methodology.
Findings
Proposing training strategies based on this methodology encourages both the reconstruction of future teachers' practical knowledge and also adequate professional development from initial training.
Research limitations/implications
The main constraint in the study was the cost-benefit ratio, since this experience has required significant practical and emotional dedication by the people involved, while the expected results have only been partially evident in the students. This would seem to imply that the strategy requires continuity over time in order for future education professionals to take it fully on board.
Practical implications
More continuity in such experiences would be required in order to fully analyse their actual value. To this end, the experiences need to be more closely related to the university curriculum, and there must be greater coordination between the subjects in order to ensure a holistic approach to LS.
Originality/value
This article sets out an LS experience as a collaborative action-research strategy that promotes the reconstruction of students' practical knowledge and their professional development in initial training.
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