Grouting experiment and goaf treatment of reservoir dam foundation
1. Introduction
There is a large area of goaf of small coal mines below the dam foundation and reservoir area of Hongshimao Reservoir in Zichang County, Shaanxi Province. Once the goaf becomes unstable, it will directly cause instability and damage to the dam body or ancillary buildings, which will not only directly affect the normal water storage of the reservoir, but also have a great impact on the safety of farmland, infrastructure and people's lives and properties in the lower reaches. At home and abroad, there is no engineering experience of reservoir-building project above coal mine goaf.
Figure 1 Layout plan of goaf below Zichang Reservoir
Figure 2 Schematic diagram of goaf section below the dam foundation
2. Solution
In order to solve the complicated rock water engineering problems such as reservoir leakage and dam seepage damage caused by goaf in dam foundation, the treatment scheme was adopted: First step, filling grouting treatment for dam foundation and goaf in the reservoir area. The goaf was filled with cement fly ash slurry through vertical boreholes and directional boreholes to eliminate the "activation" space of goaf and to control the potential settlement and deformation in the dam foundation and reservoir area. Second step, deep seepage control grouting treatment for goaf under the curtain line of dam foundation. By adopting the bottom-up sectional grouting technology, the stratum fissures and voids caused by mining activities under the curtain line were grouted and consolidated, and the stratum leakage problem from the shallow impervious curtain line to the floor of the goaf was solved.
Figure 3 Design layout plan and cross-section of the directional boreholes and grouting along the goaf of the coal seams
3. Construction situation
The treatment project lasted 82 days, the filling and grouting works of the goaf below the dam foundation and in the reservoir area, and the deep anti-seepage grouting of the goaf under the curtain line of dam foundation were completed.
Figure 3 Filling and grouting works of the goaf in dam foundation and reservoir area
Figure 4 Deep anti-seepage grouting works in the goaf under the curtain line of the dam foundation
4. Achieved accomplishment
The project eliminates the "activation" space in the goaf, solves the settlement and deformation of dam foundation and its ancillary structures, improves the permeability of strata and meets the anti-seepage requirements of dam construction. After grouting works, the water pressure test results show that the water permeability of every stratum decreases, among which the water permeability of sandstone in shallow section of dam foundation is 4.0Lu and 3.9Lu, and the water permeability of mudstone, sandstone, coal seam and stone layer in deep dam foundation after grouting decreases by 51.1%, 54.4% and 48.5% respectively compared with the water permeability of non-mining layers.
Figure 4 Comparison of formation permeability before and after grouting
5. FAQ
Q1: What can you do in this field?
A: We are committed to solving the geological disasters in goafs encountered during the construction of various projects, and have formed a complete set of technical systems including goaf exploration, stability evaluation, design, construction and post-construction detection.
Hot Tags: grouting experiment of reservoir dam foundation, China, manufacturers, suppliers, factory, wholesale, price list, buy, for sale,
