Foreword
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GB/T 16453 consists of the following six parts under the general title Comprehensive control of soil and water conservation - Technical specification:
——GB/T 16453.1-2008 Comprehensive control of soil and water conservation - Technical specification - Technique for erosion control of slope land;
——GB/T 16453.2-2008 Comprehensive control of soil and water conservation - Technical specification - Technique for erosion control of waste land;
——GB/T 16453.3-2008 Comprehensive control of soil and water conservation - Technical specification - Technique for erosion control of gullies;
——GB/T 16453.4-2008 Comprehensive control of soil and water conservation - Technical specification - Small engineering of store, drainage and draw water;
——GB/T 16453.5-2008 Comprehensive control of soil and water conservation - Technical specification - Technique for erosion control of wind erosion;
——GB/T 16453.6-2008 Comprehensive control of soil and water conservation - Technical specification - Technique for erosion control of collapse hill.
This part replaces GB/T 16453.3-1996 Comprehensive control of soil and water conservation - Technical specification - Technique for erosion control of gullies.
The following changes have been made with respect to GB/T 16453.3-1996:
a) the planning for erosion control of gullies is changed to layout;
b) anti-seepage treatment for gully head is added;
c) the timber support in cantilever gully head protection works is changed to cement stake;
d) the stepped check dam is changed to dry stone check dam;
e) the gravity-type check dam is changed to stone masonry check dam;
f) the requirement to plant shrubs and grasses on the check dam to strengthen soil fixation during the construction of the check dam is added.
Annexes A, B and C to this standard are informative.
This part was proposed by the Ministry of Water Resources of the People's Republic of China.
This part is under the jurisdiction of the Department of International Cooperation, Science and Technology, MWR.
The previous edition of this part is as follows:
——GB/T 16453.3-1996.
Introduction
GB/T 16453.3-1996 has been implemented for more than ten years, and has played an important guiding role in comprehensive control of soil and water conservation. With the development of social economy and the change of rural industrial structure in China, the content and nature of soil and water conservation work have also undergone profound changes. In order to adapt to the soil and water conservation work under the new situation and further standardize the technical specifications for comprehensive control of soil and water conservation, the standard was revised according to the unified arrangement of the Department of International Cooperation, Science and Technology and the Department of Soil and Water Conservation, MWR.
Comprehensive control of soil and water conservation - Technical specification - Technique for erosion control of gullies
1 Scope
1.1 This part of GB/T 16453 specifies the technical requirements for survey, planning, engineering layout and hydrological calculation of gully head protection works, check dam works and check dam for farmland forming works as well as the design, construction, and engineering management of structures and utilization of farmland formed in silt storage dam.
1.2 The application scope of this part is as follows:
a) the gully head protection works and check dam works are partially applicable to the tableland, hilly area, gentle hilly area and earth-rock mountainous area in the northern China (Northwest, Northeast and North China);
b) the check dam for farmland forming works are partially applicable to the loess areas in Northwest, North and Northeast China. It may also serve as a reference for dams constructed in gullies having the function of retaining mud and silting land (including sediment trapping dam in southern China) in erosion control of gullies in other areas of China. The check dams for farmland forming in this part are mainly rolled homogeneous earth dams. For the design and construction of sluicing-siltation dam, only some principles are specified in this part. See SL302 for details.
2 Normative references
The following documents contain provisions which, through reference in this part of GB/T 16453, constitute provisions of this part. For dated references, subsequent amendments (excluding corrections) to, or revisions of, any of these publications do not apply to this part. However parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 15772-2008 Comprehensive control of soil and water conservation - General rule of planning
GB/T 15774 Comprehensive control of soil and water conservation - Method of benefit calculation
GB/T 16453.4 Comprehensive control of soil and water conservation - Technical specification - Small engineering of store, drainage and draw water
SL 289 Technical code of key dam for soil and water conservation
SL 302 Technical specification for sluicing-siltation earth dam
3 Gully head protection works
3.1 Basic requirements
3.1.1 The gully head protection works shall cooperate with erosion control measures of gullies such as check dam and check dam for farmland forming in the overall planning and comprehensive control of small watersheds, so as to jointly control the gully development.
3.1.2 The key position for construction of gully head protection works shall be: position causing development and expansion of gully head where the slope rainstorm runoff is concentrated and discharged into the gully head through the natural catchment troughs on the slope above the gully head.
3.1.3 The main tasks of the gully head protection works shall be: preventing the slope rainstorm runoff from entering the gully from the gully head or to making it enter the gully in a controlled way to stop the gully head from development and protect the ground from being cut and damaged by the gully.
3.1.4 When the incoming water from the slope is not only concentrated at the gully head, but also enters the gully through runoff scattered at the gully edge, the ridge along gully shall be constructed around the gully edge while the gully head protection works are constructed, so as to prevent the slope runoff from entering the gully.
3.1.5 The defense standard of gully head protection works shall be maximum rainstorm of 3h to 6h once in 10 years. Depending on the rainfall conditions of each region, locally prevalent short-duration, high-intensity rainstorm that is most likely to cause severe soil erosion and water loss may be considered.
3.1.6 When the catchment area above the gully head is large (more than 10hm2), corresponding slope control measures and minor water storage works shall be arranged to reduce the concentration of surface runoff at gully head.
3.2 Layout of gully head protection works
3.2.1 Storage gully head protection works
a) Ridge type. At 3m to 5m above the gully head, a soil ridge is constructed around the gully head to stop the runoff from entering the gully.
b) Ridge reservoir type. When the water inflow above the gully head cannot be completely blocked by the ridge alone, a reservoir shall be constructed near the low-lying area above the ridge to partially block the inflow from the slope. The reservoir is jointly used with the ridge to prevent runoff from entering the gully.
3.2.2 Drainage gully head protection works
a) Water-drop type. When the height difference of steep cliff (or steep slope) at the gully head is small, it is constructed into water drop with mortar rubble, and energy dissipation equipment is arranged below it, so that the water flow can safely enter the gully through water drop.
b) Cantilever type. When the height difference of steep cliff at the gully head is large, the plastic or pottery cantilever pipe is placed on the scarp at the soil gully head to drain water down the gully, and the energy dissipation facility will be arranged at the bottom of the gully.
3.3 Design
3.3.1 Design of storage gully head protection works
3.3.1.1 The water inflow may be calculated using Equation (1):
W=10KRF (1)
where,
W——the water inflow, m3;
F——the catchment area above the gully head, hm3;
R——the maximum rainfall of 3h to 6h in rainstorm once in 10 years, mm;
K——the runoff coefficient.
3.3.1.2 The section and position requirements of the ridge are as follows:
a) The ridge shall have a soil trapezoidal section, with a height of 0.8m to 1.0m, a top width of 0.4m to 0.5m, and a ratio of internal slope to external slope of about 1:1.
b) The position of ridge shall be determined according to the depth of the gully head. Generally, if the depth of the gully head is less than 10m, the position of the ridge is 3m to 5m away from the gully head.
Foreword i
Introduction iii
1 Scope
2 Normative references
3 Gully head protection works
4 Check dam works
5 Check dam for farmland forming works
Annex A (Informative) Calculation method of catchment area
Annex B (Informative) Plotting method of water level-farmland area curve and water level-storage capacity curve
Annex C (Informative) Calculation method of earthwork volume of dam body
