NB/T 10236-2019Specification for hydrogeological investigation of hydropower projects (English PDF)

Foreword

This document was issued on 4 November 2019 by the National Energy Administration of the PRC and takes effect on 1 May 2020.

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 prepared by the drafting group in accordance with the requirements of the Notice of the National Energy Administration on Issuing the Second Batch of the 2014 Plan for the Formulation (and Revision) of Industry Standards in the Energy Sector (Guo Neng Ke Ji [2015] No. 12). The drafting group carried out extensive investigation and research, carefully summarized practical experience, and prepared the specification on the basis of a wide solicitation of comments.

The main technical content of this specification is: regional hydrogeological investigation; hydrogeological investigation in the reservoir area; hydrogeological investigation in the dam site area; hydrogeological investigation along the water diversion route area; hydrogeological investigation in the underground powerhouse area; hydrogeological investigation of slopes; and the results (deliverables) of hydrogeological investigation.

This specification is under the administration of the National Energy Administration. It was proposed by, and is under the routine management of, the China Renewable Energy Engineering Institute (General Institute of Hydropower and Water Resources Planning and Design).

The Standardization Technical Committee for Hydropower Investigation and Design of the energy industry is responsible for the interpretation of the specific technical content of this specification.

Comments and suggestions arising during the implementation of this specification should be sent to the China Renewable Energy Engineering Institute (address: No. 2 Liupukang Beixiaojie, Xicheng District, Beijing; postcode 100120).

Chief drafting organization of this specification: PowerChina Kunming Engineering Corporation Limited.

Participating drafting organizations of this specification: PowerChina Huadong Engineering Corporation Limited; PowerChina Guiyang Engineering Corporation Limited; PowerChina Zhongnan Engineering Corporation Limited; Hohai University.

Chief drafters of this specification: Wang Kun, Wang Yiyuan, Cheng Wei, Zhou Zhifang, Wang Yonghui, Shan Zhigang, Guo Weixiang, Wang Liangtai, Sun Chaobi, Yao Cuixia, Cui Xiaodong, Duan Weifeng, Zhou Chunhong, Zhang Guofu, Li Yue, Yang Yun, Peng Senliang, Wu Yong.

Chief reviewers of this specification: Yang Jian, Zhu Jianye, Li Wengang, Yang Jianhong, Wu Yongfeng, Wang Huiming, Wan Jinnian, Zhong Jianping, Wang Yaqun, Liu Zengjie, Wei Shangchao, Hu Jisong, Ao Renjun, Xu Mo, Zhao Yi, Li Shisheng.

Approval and publication data

This specification is an Energy Industry Standard of the People's Republic of China, designation NB/T 10236-2019, Chinese title: Shuidian Gongcheng Shuiwen Dizhi Kancha Guicheng; English title printed on the cover: Specification for Hydrogeological Investigation of Hydropower Projects.

The standard was approved by the National Energy Administration through Announcement No. 6 of 2019, dated 4 November 2019, which approved 384 energy industry standards (Annex 1), 48 English versions of energy industry standards (Annex 2), 7 No. 1 amendment sheets to energy industry standards (Annex 3), and abolished 5 energy industry standards and standard plans (Annex 4).

In the Catalogue of Industry Standards attached to that announcement (Annex 1), this specification appears as item 13: standard number NB/T 10236-2019, title Specification for Hydrogeological Investigation of Hydropower Projects, approval date 2019-11-04, implementation date 2020-05-01. The columns for the superseded standard and for the adopted international standard are blank, so this specification does not replace any earlier standard and is not an adoption of an international standard.

Editor-in-chief department: China Renewable Energy Engineering Institute. Approving department: National Energy Administration. Date of entry into force: 1 May 2020.

Classification data printed on the cover: ICS 27.140 (Hydraulic engineering), Chinese Standard Classification Code P 59.

Published and distributed by China Water and Power Press, No. 1 Yuyuantan South Road, Building D, Haidian District, Beijing 100038; printed by Qingsong Yongye (Tianjin) Printing Co., Ltd.

Publication particulars: format 140 mm by 203 mm, 32-mo, 4 printed sheets, 108 thousand characters; first edition May 2020, first printing May 2020; print run 0001 to 2000 copies.

Book number 155170-627; list price 110.00 yuan. All rights reserved; infringement will be prosecuted.

Structure of the specification

The specification is organized in ten numbered chapters followed by fourteen appendices (A, B, C, D, E, F, G, H, J, K, L, M, N and P) and by the back matter, as set out in the Contents page reproduced word for word in the table of contents of this record.

Chapter 1, General Provisions, page 1, states the purpose, the field of application and the relationship of this specification with other current national standards.

Chapter 2, Terms, page 2, defines the seventeen terms used throughout the specification, each with its English equivalent.

Chapter 3, Basic Requirements, page 4, sets out the general technical requirements applicable to every kind of hydrogeological investigation covered by the specification.

Chapter 4, Regional Hydrogeological Investigation, page 6, covers the investigation carried out at regional scale around the project area.

Chapter 5, Hydrogeological Investigation in Reservoir, page 7, is divided into 5.1 General Requirements, 5.2 Investigation Content, 5.3 Investigation Methods and 5.4 Evaluation of Hydrogeological Problems.

Chapter 6, Hydrogeological Investigation at Dam Site, page 14, is divided into 6.1 General Requirements, 6.2 Investigation Content, 6.3 Investigation Methods and 6.4 Evaluation of Hydrogeological Problems.

Chapter 7, Hydrogeological Investigation Along Water Diversion, page 21, is divided into 7.1 General Requirements, 7.2 Investigation Content, 7.3 Investigation Methods and 7.4 Evaluation of Hydrogeological Problems.

Chapter 8, Hydrogeological Investigation in Underground Powerhouse, page 26, is divided into 8.1 General Requirements, 8.2 Investigation Content, 8.3 Investigation Methods and 8.4 Evaluation of Hydrogeological Problems.

Chapter 9, Hydrogeological Investigation at Slope, page 30, is divided into 9.1 General Requirements, 9.2 Investigation Content, 9.3 Investigation Methods and 9.4 Evaluation of Hydrogeological Problems.

Chapter 10, Hydrogeological Investigation Results, page 33, covers the deliverables of the hydrogeological investigation.

Appendix A, Application Requirements for Remote Sensing Hydrogeological Interpretation, page 35.

Appendix B, Requirements for Digital Hydrogeological Mapping, page 38.

Appendix C, Requirements for Building a Hydrogeological Information Database, page 40.

Appendix D, Selection of Geophysical Techniques for Hydrogeological Investigation, page 41.

Appendix E, Common Formulae for Analytical Calculation of Reservoir Leakage, page 42.

Appendix F, Value Selection for Permeability Coefficient and Permeable Rate of Rock Mass and Soil Mass, page 44.

Appendix G, Common Formulae for Analytical Calculation of Groundwater Backwater, page 45.

Appendix H, Directional Water Pressure Test of Rock Mass, page 48.

Appendix J, Calculation for Dam Foundation and Bypass Leakage, page 54.

Appendix K, Water Inflow Calculation in Tunnel, page 59.

Appendix L, Canal Leakage Calculation, page 66.

Appendix M, Water Inflow Calculation in Underground Powerhouse, page 72.

Appendix N, Water Inflow Calculation by Big Well Method, page 74.

Appendix P, Calculation for Slope Porewater Pressure Head, page 76.

Explanation of Wording in This Specification, page 80, gives the meaning of the degrees of obligation used in the text.

List of Quoted Standards, page 81, lists the standards referred to in the provisions.

Addition: Explanation of Provisions, page 83, is the commentary on the individual clauses.

1 Scope

NB/T 10236-2019 sets out how the hydrogeology of a hydropower site is investigated. Groundwater decides several of the questions that matter most on a dam project: whether the reservoir will leak around the abutments or into an adjacent valley, how much water will enter a tunnel and at what pressure, whether the foundation can be dewatered and what the uplift beneath the dam will be, and whether the groundwater will attack concrete. The specification fixes the scope and depth of investigation at each design stage, from planning through feasibility to detailed design and construction. It covers the mapping and survey work, the drilling and the observation boreholes, the in-situ testing - water pressure testing in rock, pumping and injection tests, tracer testing to establish flow paths, and the measurement of permeability in soil and rock - and the laboratory analysis of water chemistry and of its aggressiveness to concrete and steel. Groundwater level monitoring and its interpretation, the delineation of aquifers and aquitards, karst investigation where it applies, and the assessment of reservoir leakage, of seepage around and beneath structures, and of tunnel inflow and water inrush risk each receive their own treatment. The specification closes with the calculations and models used, the criteria for the design of grout curtains and drainage, and the content of the hydrogeological report. It applies to hydropower projects of all grades in China.

1.0.1 This specification is formulated in order to standardize the technical requirements for the content, the methods and the evaluation of hydrogeological investigation of hydropower projects, and to ensure the quality of the work and the quality of its results.

1.0.2 This specification applies to the hydrogeological investigation of hydropower projects other than those in karst areas.

1.0.3 In addition to complying with this specification, the hydrogeological investigation of hydropower projects shall also comply with the provisions of the relevant current national standards.

2 Terms

2.0.1 Hydrogeological investigation. The work carried out by means of various investigation techniques in order to ascertain the hydrogeological conditions of the project area and to evaluate the engineering hydrogeological problems and the environmental hydrogeological problems of the project.

2.0.2 Hydrogeological conditions. The general term for the characteristics of the occurrence (burial), distribution, recharge, runoff and discharge conditions, water quality and water quantity of groundwater, together with the factors that influence them.

2.0.3 Hydrogeological unit. An area with comparatively definite boundaries and with relatively independent recharge, runoff and discharge conditions, delimited on the basis of the differences in hydrogeological conditions.

2.0.4 Groundwater system. The general term for the basic groundwater units, and their combinations, that are bounded by geological boundaries, that have input, transfer and output of water quantity, water quality, energy and other information, and that possess a unified hydraulic connection; it comprises water-bearing systems and flow systems.

2.0.5 Hydrogeological structure. The spatial distribution and combination of rock masses and soil masses having different permeability.

2.0.6 Groundwater type. The classification of groundwater according to the characteristics of the medium, the burial conditions, the circulation interval, the water-storage structure, the hydrochemical composition, the water temperature and similar features.

2.0.7 Engineering hydrogeological problem. A geological problem connected with groundwater activity that is induced by, or suffered during, the construction and operation of the project and that has an adverse effect on the project.

2.0.8 Environmental hydrogeological problem. The adverse effect produced on the surroundings of the project by the changes in the groundwater environmental conditions caused by the construction and operation of the project.

2.0.9 Hydrogeological parameters. The indexes that characterize the hydrogeological properties of rock masses and soil masses.

2.0.10 Aquifer. A saturated rock or soil stratum that is able to store and to transmit water and to yield a certain quantity of gravity water.

2.0.11 Permeable stratum. A rock or soil stratum with a comparatively strong capacity to transmit water.

2.0.12 Relatively impermeable stratum. A rock or soil stratum whose capacity to transmit water is relatively weak.

2.0.13 Hydrogeological test. The various measurements and tests carried out in order to evaluate the hydrogeological conditions and to obtain the hydrogeological parameters of the rock and soil strata.

2.0.14 Groundwater regime. The variation with time of the groundwater level, water quantity, water temperature, chemical composition and other elements of groundwater under the combined influence of natural factors, engineering activities and other factors.

2.0.15 Groundwater balance. The quantitative balance relationship, within a given period of time and within a hydrogeological unit or a groundwater system, among the total recharge of groundwater, the total quantity consumed by discharge and the groundwater storage.

2.0.16 Conceptual hydrogeological model. A pattern that generalizes the actual boundary types, internal structure, permeability properties, hydraulic characteristics and recharge and discharge conditions of an aquifer so as to make mathematical and physical simulation convenient.

2.0.17 Groundwater numerical model. A set of mathematical expressions established on the basis of the conceptual hydrogeological model and able to approximate the structure, the movement characteristics and the various seepage elements of the actual groundwater system.

3 Basic requirements

3.0.1 The hydrogeological investigation shall ascertain the hydrogeological conditions of the project area, shall analyse and evaluate the hydrogeological problems, and shall put forward the geological basis and the recommendations required for the engineering design.

3.0.2 The division of the hydrogeological investigation into stages, and the depth of the investigation, shall comply with the relevant provisions of the current national standard Code for Hydropower Engineering Geological Investigation, GB 50287.

3.0.3 Hydrogeological investigation may be divided into general hydrogeological investigation and special hydrogeological investigation, and shall comply with the following requirements.

3.0.3 clause 1 General hydrogeological investigation shall be carried out together with the engineering geological investigation.

3.0.3 clause 2 Special hydrogeological investigation is advisable in areas where serious leakage and large-area inundation may occur; special hydrogeological investigation may also be carried out when the hydrogeological conditions change markedly during construction and cause a major adjustment of the engineering design scheme, or when major hydrogeological problems appear during the operation of the project.

3.0.4 The work of general hydrogeological investigation shall comply with the following requirements.

3.0.4 clause 1 The data already available for the project area shall be collected and analysed.

3.0.4 clause 2 Methods such as hydrogeological survey and mapping, geophysical exploration, drilling, pit and trench exploration, testing and observation may be adopted.

3.0.4 clause 3 The selection of the scale of the hydrogeological mapping at each stage shall comply with the relevant provisions of the current national standard Code for Hydropower Engineering Geological Investigation, GB 50287. In hydrogeological survey and mapping it is advisable to make use of satellite, aerial and terrestrial photographic remote sensing data and of 3S techniques. The application requirements for remote sensing hydrogeological interpretation techniques should comply with the relevant provisions of Appendix A of this specification; the content requirements for digital hydrogeological mapping should comply with the relevant provisions of Appendix B of this specification; and the content requirements for building the hydrogeological information database should comply with the relevant provisions of Appendix C of this specification.

3.0.4 clause 4 Hydrogeological geophysical exploration shall give full consideration to the physical property characteristics of the object to be detected and shall employ effective methods for comprehensive detection. The detection results at key points and in typical sections shall be verified by drilling or by other means. The selection of the geophysical methods for hydrogeological investigation should comply with the relevant provisions of this specification (the sentence continues beyond page 4, which is the last page of the extract available).