NB/T 10139-2019Specification for investigation and control design of debris flow for hydropower projects (English PDF)

Foreword

This document was issued on 4 June 2019 by the National Energy Administration of the PRC and takes effect on 1 October 2019.

It is a NB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

It is classified under ICS 27.140, Chinese classification P 59.

This specification has been formulated in accordance with the requirements of the Notice of the National Energy Administration on Issuing the Second Batch of the 2012 Plan for the Formulation (Revision) of Industry Standards in the Energy Field (Guo Neng Ke Ji [2012] No. 326). During its preparation the drafting group carried out extensive investigation and research, earnestly summarized practical experience, referred to relevant advanced standards at home and abroad, and prepared this specification on the basis of widely soliciting opinions.

The main technical contents of this specification are: content of debris flow investigation, methods of debris flow investigation, engineering geological assessment of debris flow, debris flow control standards, design of debris flow control works, debris flow monitoring and forewarning, construction planning of debris flow treatment projects, and debris flow investigation and design reports.

This specification is under the administration of the National Energy Administration. It was proposed by the General Institute of Hydropower and Water Resources Planning and Design, which is also responsible for its routine administration, while the Standardization Technical Committee for Hydropower Investigation and Design of the Energy Industry is responsible for the interpretation of its specific technical content.

Should any comment or suggestion arise during the implementation of this specification, please send it to the General Institute of Hydropower and Water Resources Planning and Design (address: No. 2 Liupukang Beixiaojie, Xicheng District, Beijing; postcode 100120).

Chief editing organization of this specification: PowerChina Chengdu Engineering Corporation Limited.

Participating organization of this specification: PowerChina Huadong Engineering Corporation Limited.

Chief drafters of this specification: Chen Weidong, Peng Shiwei, Fu Zheng, Yu Xueming, Shan Zhigang, Li Qingchun, Song Shuzhi, Wei Fang, Cao Qiang, Ren Jiuming, He Xingyong, Wang Jingyong, Zeng Yong, Qin Guanghui, Yang Shiming, Zhou Deyan and Liu Xia.

Chief reviewers of this specification: Yang Jian, Dang Lincai, Fang Guangda, Li Xiangfeng, Wang Mingtao, Li Wengang, Deng Yiguo, Mi Yingzhong, Zhong Huiya, Ju Guanghong, Feng Hanbin, Zhang Guofu, Xie Hong, Hu Xiewen, Piao Ling, Cao Yuanyuan and Li Shisheng.

Issue and Approval

Energy industry standard of the People's Republic of China NB/T 10139-2019, Specification for Investigation and Control Design of Debris Flow for Hydropower Projects. Chief editing department: General Institute of Hydropower and Water Resources Planning and Design. Approving department: National Energy Administration. Date of implementation: 1 October 2019. Published in Beijing in 2019.

National Energy Administration Announcement No. 4 of 2019: the National Energy Administration approved 297 industry standards, including the Code for Electrical Design of Photovoltaic Power Generation Projects, among which 105 are energy standards (NB), 168 are electric power standards (DL) and 24 are petrochemical standards (NB/SH), and hereby issues them. Attachment: catalogue of industry standards. National Energy Administration, 4 June 2019.

In the attached catalogue of industry standards this specification appears under serial number 12: standard number NB/T 10139-2019, standard title Specification for Investigation and Control Design of Debris Flow for Hydropower Projects, with no superseded standard and no adopted international standard shown, approval date 4 June 2019 and implementation date 1 October 2019.

The cover of the standard bears the international classification ICS 27.140 and the Chinese standard classification code P 59, with the document filed under class P. The standard was issued on 4 June 2019 by the National Energy Administration and came into force on 1 October 2019.

1 Scope

NB/T 10139-2019 covers the investigation of debris flows on hydropower projects and the design of the works that control them. A debris flow is a moving mass of water, mud and boulders coming down a steep gully, and on a mountain hydropower site it threatens exactly the things that cannot be moved: the dam and its abutments, the powerhouse, the access roads, the construction camps and spoil areas, and the reservoir itself, which a large flow can partly fill. The specification sets the general provisions and the defined terms, then the basic requirements by design stage and by the importance of what is being protected. Investigation comes first: the identification and mapping of debris flow gullies, the geomorphological and geological survey of the source area, the assessment of the loose material available, the rainfall that triggers a flow, and the historical record. From that it sets out how the flow is characterised - its type, its scale and recurrence, the peak discharge, the density, the velocity and the impact force, and the run-out and deposition expected. Control design follows, covering the whole family of measures: check dams and sabo works, drainage and diversion channels, deposition basins, guide dykes, slope stabilisation and revegetation in the source area, and the crossing structures that must pass a flow safely. Monitoring, early warning and maintenance close the document. It applies to hydropower projects in China.

1.0.1 This specification is formulated in order to standardize the technical requirements for the investigation of debris flow and for the design of debris flow prevention and control works in hydropower projects.

1.0.2 This specification applies to the investigation of debris flow and to the design of debris flow prevention and control works in the engineering areas of hydropower projects, in concentrated resettlement areas for displaced people, in owner camps and in construction camps.

1.0.3 In addition to complying with this specification, the investigation of debris flow and the design of debris flow prevention and control works for hydropower projects shall also comply with the provisions of the relevant current national standards.

2 Terms

2.0.1 Debris flow: a fluid carrying a large amount of solid material, produced in a gully or on a hillslope by the action of runoff such as precipitation or glacier meltwater.

2.0.2 Debris flow hazard: a natural disaster in which a debris flow causes damage to, or endangers, human life, property, buildings and structures.

2.0.3 Debris flow influence range: the area that may be subject to effects of a debris flow such as scouring and burial by deposition.

2.0.4 Debris flow criticality: the degree of severity with which a debris flow endangers buildings, structures or the safety of persons.

2.0.5 Debris flow characteristic parameters: the indices that reflect the fluid properties, the movement characteristics and the scale of a debris flow.

2.0.6 Debris flow control: the use of non-engineering or engineering measures to prevent and treat debris flow.

2.0.7 Debris flow diversion channel: a channel-shaped flow-conveying structure that drains and discharges a debris flow.

2.0.8 Debris flow diversion tunnel: a tunnel that drains and discharges a debris flow.

2.0.9 Debris flow slit-check dam: a dam-type structure that intercepts and retains a debris flow.

2.0.10 Debris flow sediment and deposit field: a site that makes use of favourable natural topography, where retaining and storage works are built to arrest and store the solid material of a debris flow.

2.0.11 Debris flow monitoring: the surveillance and observation of the formation and the movement characteristics of a debris flow.

2.0.12 Debris flow forewarning: the monitoring of, and the issue of alarms for, debris flow hazards.

3 Basic Requirements

3.0.1 The investigation of debris flow and the design of debris flow control shall comply with the following requirements.

3.0.1-1 Debris flow shall be investigated, the development tendency of the debris flow shall be analysed, and the influence of the debris flow hazard shall be evaluated.

3.0.1-2 For debris flow gullies that exert an influence, comparison and selection of control schemes shall be carried out, and specific design work shall be carried out for the selected scheme.

3.0.2 The investigation of debris flow should be divided into three steps: preliminary survey, particular investigation and investigation for the treatment project.

3.0.3 The design of debris flow control should be divided into two steps: design of the control scheme and construction drawing design.

3.0.4 The working procedure for the investigation of debris flow and for the design of debris flow control shall comply with the following requirements.

3.0.4-1 A preliminary survey shall be carried out first; a particular investigation shall be carried out for debris flow gullies that have an influence on the project site or that require prevention and control; an investigation for the treatment project shall be carried out for debris flow gullies that need to be treated.

3.0.4-2 On the basis of the results of the particular investigation, comparison and selection of the control scheme shall be carried out; on the basis of the results of the investigation for the treatment project, the design of the treatment works and the construction drawing design shall be carried out for the selected scheme.

3.0.4-3 The steps of investigation and design may be combined and carried out together according to the development characteristics of the debris flow and the needs of prevention and control.

3.0.5 The content of the assessment made in the investigation of debris flow shall comply with the following requirements.

3.0.5-1 The preliminary survey shall investigate the gullies that may endanger the sites and the buildings and structures to be planned and built and the safety of persons, and shall determine whether they are debris flow gullies.

3.0.5-1 (continued) The preliminary survey shall make a preliminary evaluation of the development of the debris flow and of the degree of harm it may cause.

3.0.5-1 (continued) The preliminary survey shall put forward an opinion on whether a particular debris flow investigation needs to be carried out.

3.0.5-2 On the basis of the preliminary survey of the debris flow, the particular investigation shall ascertain the physical geography and the geological environment in which the debris flow develops, as well as the conditions of formation, the development characteristics and the characteristic parameters of the debris flow.

3.0.5-2 (continued) The particular investigation shall analyse the debris flow hazard and demonstrate the necessity of debris flow prevention and control; it shall carry out a geological evaluation for the selection of the project site, for route selection and for the layout, and shall put forward debris flow control schemes and recommended measures.

3.0.5-3 On the basis of the particular investigation, the investigation for the treatment project shall ascertain the engineering geological conditions of the area of the treatment works, shall check and review the debris flow characteristic parameters required by the design, shall provide the physical and mechanical parameters of the rock and soil masses, and shall carry out an engineering geological analysis and evaluation.

3.0.6 The content of the design for debris flow prevention and control shall comply with the following requirements.

3.0.6-1 Control schemes shall be drawn up on the basis of the characteristics of the debris flow, the topographic and geological conditions, the hydrological conditions, the objects affected and the degree of harm; the schemes shall be compared and selected by taking into overall account such factors as the treatment effect, the conditions of construction and of operation and maintenance, and the investment, and the control scheme shall then be selected.

3.0.6-2 On the basis of the selected control scheme, the location and the type of the structures of the treatment works shall be determined and a construction planning scheme shall be prepared.

3.0.6-2 (continued) The content and the layout of the debris flow forewarning and monitoring shall be determined and the budgetary estimate of the control works shall be prepared.

3.0.6-2 (continued) The requirements for the operation and maintenance of the treatment works shall be put forward.

3.0.6-3 The construction drawing design shall provide the detailed design of the structures of the treatment works in combination with the conditions at the site.

3.0.7 A corresponding debris flow investigation and design report should be prepared for each step of investigation and design.

3.0.7 (continued) The report should include the main text, attached drawings and annexes.