The first author proposed the concept of the cemented material dam （CMD） in 2009. This concept was aimed at building an environmentally friendly dam in a safer and more economical way for both the dam and the area d...The first author proposed the concept of the cemented material dam （CMD） in 2009. This concept was aimed at building an environmentally friendly dam in a safer and more economical way for both the dam and the area downstream. The concept covers the cemented sand, gravel, and rock dam （CSGRD）, the rockfill concrete （RFC） dam （or the cemented rockfill dam, CRD）, and the cemented soil dam （CSD）. This paper summarizes the concept and principles of the CMD based on studies and practices in projects around the world. It also introduces new developments in the CSGRD, CRD, and CSD.展开更多
To deal with the construction difficulties of Xiangjiaba underground hydropower station,such as complex geological conditions,narrow rock bench,high loading,high quality requirements and urgent time limit,the project ...To deal with the construction difficulties of Xiangjiaba underground hydropower station,such as complex geological conditions,narrow rock bench,high loading,high quality requirements and urgent time limit,the project adopted the concept of precision blasting.The explosive energy and rock mass fragmentation were well controlled by taking reasonable excavation sequence,designing steel pipe drilling frame,the additional techniques of double layer smooth blasting,evenly micro charge,staggered arrangement of boreholes and pre-stressed anchors.These technologies ensured the excavation quality of the rock face beam,achieving successful blasting results:Semi hole ratio was 100%in Ⅱ surrounding rock,99.2%in Ⅲ surrounding rock and 90%~ 97.3%in Ⅳ surrounding rock;underbreak was avoided and the average backbreak was only2.9 cm;the unevenness was 0 ~ 4 cm;the influence depth of blasting and unloading was 0.2 ~ 0.7 cm.展开更多
文摘The first author proposed the concept of the cemented material dam （CMD） in 2009. This concept was aimed at building an environmentally friendly dam in a safer and more economical way for both the dam and the area downstream. The concept covers the cemented sand, gravel, and rock dam （CSGRD）, the rockfill concrete （RFC） dam （or the cemented rockfill dam, CRD）, and the cemented soil dam （CSD）. This paper summarizes the concept and principles of the CMD based on studies and practices in projects around the world. It also introduces new developments in the CSGRD, CRD, and CSD.
文摘To deal with the construction difficulties of Xiangjiaba underground hydropower station,such as complex geological conditions,narrow rock bench,high loading,high quality requirements and urgent time limit,the project adopted the concept of precision blasting.The explosive energy and rock mass fragmentation were well controlled by taking reasonable excavation sequence,designing steel pipe drilling frame,the additional techniques of double layer smooth blasting,evenly micro charge,staggered arrangement of boreholes and pre-stressed anchors.These technologies ensured the excavation quality of the rock face beam,achieving successful blasting results:Semi hole ratio was 100%in Ⅱ surrounding rock,99.2%in Ⅲ surrounding rock and 90%~ 97.3%in Ⅳ surrounding rock;underbreak was avoided and the average backbreak was only2.9 cm;the unevenness was 0 ~ 4 cm;the influence depth of blasting and unloading was 0.2 ~ 0.7 cm.
