堆石混凝土坝概述及下一代混凝土坝施工技术展望

Over the past few decades,one of the most significant advances in dam construction has been the inven-tion of the rock-filled concrete(RFC)dam,which is constructed by pouring high-performance self-compacting concrete(HSCC)to fill the voids in preplaced large rocks.The innovative use of large rocks in dam construction provides engineers with a material that requires less cement consumption and hydration heat while enhancing construction efficiency and environmental friendliness.However,two fundamental scientific issues related to RFC need to be addressed:namely,the pouring compactness and the effect of large rocks on the mechanical and physical properties of RFC.This article provides a timely review of fundamental research and innovations in the design,construction,and quality control of RFCdams.Prospects for next-generation concrete dams are discussed from the perspectives of envi-ronmental friendliness,intrinsic safety,and labor savings.

Appraisal of the Production-Oriented Approach： An Introduction

The production-oriented approach （POA） has been developed over a decade. It is driven by the need to improve English classroom instruction for university students in China （Wen, 2016）. It is also motivated by the aspiration to enhance the quality of foreign language education in other similar pedagogical contexts outside China. A volume of research has been done by Wen Qiufang and her research team, to formulate the theory of POA and to test its effectiveness in classroom pedagogy （e.g. Wen, 2016, 2015; Yang, 2015; Zhang, 2015）. At the moment, the POA is still at an early stage of theory building and almost all empirical research is done in the Chinese context. In order to improve the quality of this theory and to make it intelligible to the international academic community, a one-day symposium was held in Beijing Foreign Studies University on May 15, 2017. The symposium was entitled ＇The first international forum on innovative foreign language education in China： Appraisal of the POA＇. In the forum, leading experts in applied linguistics were invited to discuss the strengths and weaknesses of the POA and the directions for its future development. The symposium was the first attempt for the POA research team to discuss its latest work with international scholars. This Viewpoint section collects the responses of four experts who participated in the symposium, listed in alphabetical order. The collection of articles covers three topics related to the POA： its pedagogical application, its use for teacher training, and its research. Alister Cumming is Professor Emeritus and the former Head of the Centre for Educational Research on Languages and Literacies, University of Toronto, Canada. His article focuses primarily on POA research as an exemplary case of design-based research. Rod Ellis is Research Professor in the School of Education at Curtin University, Australia. He discusses POA in terms of pedagogy, teacher training and research, with both critiques and constructive suggestions. Paul Kei Matsuda is Professor of English and Director of Second Language Writing at Arizona State University, the writed states. He responds to POA from the perspective of an expert researcher and teacher of L2 writing. Charlene Polio is Professor and Associate Chair in the Department of Linguistics ＆ Germanic, Slavic, Asian ＆ African Languages atMichigan State University, the writed states. She conceptualises POA as a useful method to address some issues in pre-service teacher development. Overall, the articles in this section are insightful and reader-friendly. They are not only useful for the development of POA in particular, but may also be valuable to a broad range of researchers as they touch upon pertaining issues, as well as emerging topics, in the field of applied linguistics. We therefore find it necessary to make them accessible to a wide readership.