SL 47-2020 in English
VALIDTechnical specification for excavation construction of rock-foundation of hydraulic structures
- Issued on:2020-11-02
- Implemented on:2021-02-02
- File Format:PDF
- Delivery:Via email within 10 business days
$1,077.00
本标准适用于水利水电工程水工建筑物岩石地基明挖施工。
Introduction
Background and significance of the standard revision
SL 47-2020 replaces the 1994 version of the standard, adds 6 new chapters such as geological survey and non-blasting excavation, and includes blasting safety monitoring in mandatory provisions. The revised standard is more in line with the requirements of modern water conservancy projects for refined construction and ecological protection.
Comparison of core technical requirements
| Technical elements | SL 47-94 | SL 47-2020 | Main points of change |
|---|---|---|---|
| Blasting control | Single-stage charge ≤300kg | Adjacent foundation surface ≤100kg | Stricter control |
| Protective layer thickness | Fixed value | Determined by experiment | More scientific |
| Excavation method | Explosion method only | Add 5 non-explosion processes such as CO₂ expansion | Diversified selection |
Key technical points of blasting
Pre-splitting blasting:Requires that the semi-porosity of the intact rock mass is ≥90%, the borehole diameter is ≤110mm, and the single-stage charge is ≤50kg. The application of the Three Gorges Project shows that the use of hydraulic drilling rigs with uncoupled charges can reduce over-excavation by 30%.
Safety monitoring: Mandatory clause 5.0.4 stipulates that blasting vibration monitoring must be carried out, and the blasting vibration speed of new concrete within 28 days must be controlled below 12cm/s.
Non-explosion process selection guide
- Hydraulic splitter:Applicable to Class I-III rock mass, splitting force 300-3000 tons, requires secondary treatment with a breaker
- CO2 expansion crushing:When the hole depth is 3-6m, the hole spacing is 2-3m, suitable for sensitive environments such as residential areas
- Static crushing agent:The construction period is long but there is no vibration, and attention should be paid to the influence of water temperature
Implementation suggestions
1. Blasting tests should be carried out first in complex geological areas to determine the parameters K and α values of the particle vibration propagation formula
2. Three-dimensional laser scanning data and acoustic wave detection report are required for the acceptance of the foundation surface
3. Graded barrier facilities should be set up in the waste dump, and the pile height should not exceed 15m
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