An experimental study was carried out to investigate the static liquefaction behaviour of sand with a small amount of plastic and nonplastic fines. Five series of tests were conducted in drained and undrained conditions. The drained test results indicate not only that the failure line coincides with the critical state, but also that the development of volumetric strain during shearing was not sensitive to the initial confining pressure. In both isotropically and anisotropically consolidated undrained tests, a so-called “reverse behaviour” was consistently observed. The results were also interpreted in the critical state framework. The critical and steady state (CS/SS) data were found to trace along the same curve in e–log( p′) space, irrespective of the stress history and effective stress paths. A comparison between the isotropic consolidation line (ICL) and critical state (CS) curve showed that a small amount of fines can significantly change the shape and position of the ICL relative to the CS curve. Furthermore, the soil behaviour manifested in both drained and undrained shearing led to the development of a modified state parameter.

Building information modeling (BIM), the emerging digital technology, is undergoing increasing application in developing countries including China. Both the governmental policy and industry motivation have indicated that BIM is becoming the mainstream innovation in China’s construction industry. Nevertheless, one major concern lies in the uncertainty of BIM investment for architecture, engineering, and construction (AEC) firms. Specifically, AEC firms should have the knowledge of areas BIM investment could focus on (such as BIM software); the expected returns from BIM investment; methods to enhance the returns from BIM usage; and the risks in implementing BIM. This study adopted a questionnaire survey–based approach to address these concerns related to BIM application and risk in China. BIM practitioners from multiple AEC fields and different experience levels were recruited as the survey sample. It was found from the questionnaire survey that both internal and external collaborations should be the BIM investment priority, together with the interoperability among multiple BIM software tools. Improved multiparty communication and understanding was the highest recognized return from BIM investment. Survey participants had a high expectation of BIM application in green building projects. Subgroup analysis conveyed the information that gaining BIM practical experience would provide professionals with more confidence on returns from BIM adoption in enhancing communication and understanding. Compared to survey participants from other professions, architects tended to have more conservative views on BIM’s effect on marketing their work, project planning, and recruiting/retaining employees. The findings from this empirical study provide an overview of BIM investment, return, and implementation-related risks for AEC professionals at different stages or levels of BIM practice, as well as suggestions for relevant public authorities when developing BIM guidelines (e.g., BIM applications in prefabrication construction). As an extension of existing BIM implementation studies in developed countries, this study provides insights of BIM practical experience and associated risks in China by adopting a holistic approach and summarizing the perceptions from AEC professionals across disciplines and experience levels. The knowledge gained from this study could be further applied in other developing countries where the application of information technology is growing in AEC projects.

In this paper, the results of three series of drained tests carried out on sands using hollow cylinder apparatus are presented. The noncoaxiality, defined as the difference between the major principal stress direction and the corresponding principal strain increment direction, is investigated. In the first series of tests, the sand was isotropically consolidated before being sheared with the fixed principal stress direction. In the other two series of tests, the sand specimens were isotropically consolidated and then sheared by rotating the major principal stress axes while the deviator stress level was either fixed (pure stress rotation) or increased continuously (combined shear loading). The experimental results provide clear evidence for material noncoaxiality when the rotation of principal stress direction is involved. The results from these series of tests show that the degree of noncoaxiality depends on the level of deviatoric stress and the stress increment direction. It tends to decrease w...

Experimental results on the static liquefaction behaviour of sand under plane-strain conditions are presented in this paper. Undrained tests on very loose sand under both plane-strain and axisymmetric conditions were conducted and the results compared. The test data show that the undrained behaviour of sand under plane strain is similar to that under axisymmetric conditions. However, the critical-state line (CSL) on both the q–p′ and the e–p′ planes determined under plane-strain conditions is different from that under axisymmetric conditions. The slope of the CSL is different as a result of the influence of the intermediate principal stress. The state parameter (ψ), which is measured with reference to the CSL in the e – log p′ plane, is also different: the ψ value for plane strain is about 0.05 less than that for axisymmetric conditions for the sand tested. The instability behaviour of very loose sand under undrained plane-strain conditions is also studied. Based on the testing data, a unique relationship between the stress ratio of the instability line and ψ is established to enable the triaxial results to be used for plane-strain conditions.Key words: failure, sands, laboratory tests, liquefaction, shear strength.