GB/T 50662-2011Code for design of hydraulic structures against ice and freezing action (English PDF)

Foreword

This code was compiled by China Water Northeastern Investigation, Design and Research Co., Ltd. together with the units concerned, in accordance with the requirements of the notice of the former Ministry of Construction on the 2007 plan for the preparation and revision of engineering construction standards and codes (first batch), document Jianbiao [2007] No. 125.

This code is divided into 13 chapters and 6 appendices. Its main contents are: general provisions; terms and symbols; basic information; ice and frost-heaving loads; general provisions for materials and structures; water retaining and releasing structures; water intake and conveyance structures; canals and canal linings; structures of pump plants and hydropower stations; sluice and culvert structures; soil retaining structures (walls); bridges and flumes; and hydraulic metal structures.

This code is administered by the Ministry of Housing and Urban-Rural Development; day-to-day management is the responsibility of the Ministry of Water Resources, and the interpretation of its specific technical content is the responsibility of the General Institute of Water Resources and Hydropower Planning and Design of the Ministry of Water Resources.

The chief compiling organisation is China Water Northeastern Investigation, Design and Research Co., Ltd.; the participating organisations are the Xinjiang Uygur Autonomous Region Water Resources and Hydropower Survey and Design Institute of the Ministry of Water Resources, the Cold Region Engineering Technology Research Centre of the Ministry of Water Resources, Northwest A&F University, the State Key Laboratory of Frozen Soil Engineering of the Cold and Arid Regions Environmental and Engineering Research Institute of the Chinese Academy of Sciences, and the Heilongjiang Provincial Water Resources and Hydropower Survey and Design Institute.

The code was approved as a national standard, numbered GB/T 50662-2011, by Announcement No. 938 of the Ministry of Housing and Urban-Rural Development of 18 February 2011, and has been in force since 1 March 2012.

1 General provisions

China's national design code for hydraulic structures that have to survive ice, freeze-thaw and frost heave. North of the Yellow River the design winter is the governing case for a great deal of water infrastructure: a canal lining is lifted and cracked by the ground freezing beneath it, a sluice gate is jammed by an ice sheet that grows against it, a concrete face is spalled away over years of freezing and thawing, and an intake is blocked by frazil ice on the coldest nights of the year. The forces involved are large and unfamiliar - static ice pressure from a warming ice cover, impact from a moving one, and frost-heaving pressures normal and tangential to a buried surface - and they act on structures designed for hydraulic loads. This code sets out how to design against all of them, in thirteen chapters and six appendices: general provisions, terms and symbols, basic information, ice and frost-heaving loads, general provisions for materials and structures, and then chapter by chapter the water retaining and releasing structures, water intake and conveyance structures, canals and their linings, pump and hydropower station structures, sluice and culvert structures, retaining walls, bridges and flumes, and metal structures. It applies to the anti-ice and anti-freezing design of new or reconstructed hydraulic structures subject to ice, freeze-thaw and frost heave.

1.0.1 This code is formulated in order to unify the design standards and technical requirements for hydraulic structures against the action of ice, freeze-thaw and frost heave, and to raise the standard of anti-ice and anti-freezing design of hydraulic structures.

1.0.2 This code applies to the anti-ice and anti-freezing design of new or reconstructed hydraulic structures subject to the action of ice, freeze-thaw and frost heave.

1.0.3 The anti-ice and anti-freezing design of hydraulic structures shall comply with the following provisions: 1 it shall suit local conditions and be safe, reliable, economically rational, practical and pleasing in appearance; 2 the basic information on the natural conditions at the site of the structure and on the conditions of construction and operation shall be fully mastered; 3 the anti-ice and anti-freezing design scheme shall be determined according to the factors of the ice and frost action, the degree of harm, the class of the structure and its type, and requirements on construction and operation shall be put forward; 4 special studies shall be carried out for works severely affected by ice and frost action; 5 advanced techniques against the action of ice and frost may be adopted for particular works.

1.0.4 In addition to complying with this code, the anti-ice and anti-freezing design of hydraulic structures shall also comply with the provisions of the relevant current national standards.

3 Basic information

3.0.1 For the anti-ice and anti-freezing design of hydraulic structures, the basic information on the meteorology, the ice regime, the geology and the frozen ground at the site of the works shall be obtained as required.

3.0.2 The meteorological information shall include the annual mean air temperature at the site, the mean air temperature of the coldest month, the lowest daily mean air temperature, the freezing index, and the wind direction and wind speed in winter. The meteorological information shall be the values actually observed at the local meteorological station, or at a neighbouring station in similar conditions, over a statistical series of not less than the number of most recent years stated in this clause.

3.0.3 The division into climatic zones shall meet the following requirements: 1 where the mean air temperature of the coldest month is below the lower limit given, the zone shall be classified as a severely cold zone; 2 where it lies between the two limits given, the zone shall be classified as a cold zone; 3 where it is above the upper limit given, the zone shall be classified as a temperate zone.

3.0.4 The freezing index adopted for design shall be taken as the maximum value over the years, with a statistical series of not less than the number of most recent years stated in this clause.

3.0.5 The ice regime information shall include the date of freeze-up, the date of ice breakup, the duration of the ice run, the ice thickness, the size of the ice blocks, the ice discharge, the total volume of drifting ice, the kinds and nature of the drifting ice, and the probability of a hydraulic and climatic ice breakup. The ice regime information shall be determined from the observed data of the local river or reservoir, or of one with a similar ice regime. Where there are no measured data, it should be determined by field investigation; where the conditions for that are not available, it may be determined in accordance with Appendix A of this code.

3.0.6 The geological information shall include the kind of the foundation soil at the site, its particle composition, density, plastic limit, liquid limit, natural moisture content and the groundwater level before freezing (at the beginning of the freezing period).

3.0.7 The frozen ground information shall include the maximum freezing depth over the years and the amount of frost heave of the ground surface, each determined by the method given in this clause; the maximum freezing depth over the years shall be taken directly from the observed values at a meteorological station whose air temperature, groundwater level and soil conditions are similar to those at or near the site of the works.