摘要
中国西南山区小流域地形地貌特殊、降水充沛、物源丰富,泥石流发生频率高、灾害严重,主要采取岩土工程和生物工程措施综合防治。岩土工程措施的直接效益是拦蓄泥沙,调节泥石流固体物质总量,间接效益主要为稳沟固坡、改变沟道比降、削减泥石流流速和峰值流量、减小泥石流重度和性质、提升上游侵蚀基准面等。分析西南山区15条泥石流沟拦挡工程效益可知,拦沙坝直接减少松散固体物质总量的1.5%～48%,间接稳沟效益增加0.13%～35.39%,固坡效益增加0.01%～65.01%;谷坊直接减少物源0%～5%,间接稳沟效益增加0.04%～6.08%,固坡效益增加0.06%～33.98%。可知拦沙坝在拦挡工程防治中起主要作用,直接拦挡量是谷坊的几倍至几百倍,间接减少量为谷坊的2～10倍。生物工程措施通过增加植被覆盖率、减少地表径流、降低径流侵蚀、改善土壤结构,间接实现拦沙减沙效益。西南山区12条泥石流沟流域内植被覆盖率增幅19%～60%,间接减少泥石流物源总量达4.7%～34.6%。其中西昌市黑沙河流域植被覆盖率增加60%,侵蚀模数平均变化取值最高达9kt/(km2·a),侵蚀类型由极强变为轻度,减少物源5.894×106 m3,占物源总量的31.1%。生物工程防治效果显著。
The main features of most small watersheds in the southwest mountain areas of China include special landform, abundant rainfall and rich loose solid materials, thereby debris flows in these areas are always high frequency characteristics and natural calamities are extraordinary serious. To combine geotechnical engineering with bioengineering is a main control measure. The direct effectiveness of geotechnical engineering is to retain sediments and reduce the debris flow magnitude, and the indirect effectiveness of geotechnical engineering is to reduce bed erosion, keep the slope stable, reduce gully gradients, the debris flow velocity and peak discharge, the debris flow density, and increase the basal level of erosion, etc. By analyzing the protection effectiveness of the check dams of 15 gullies in these areas, it is found that the loose solid materials reduce by 1. 5%-48%, the indirect effectiveness of stabilizing gully bed increases by 0.13% -35.39%, and that to stabilize the slope increases by 0.01% - 65.01%. Because of check dams, the loose solid materials reduce by 0 % 5%, the indirect effectiveness of stabilizing gully bed increases by 0. 04% - 6. 08%, and the effectiveness to stabilize the slope increases by 0.06%-33. 98%. According to the above analysis results, the amount of directly detained solid materials by sediment storage dam is several times to hundreds of times larger than that by check dams, and the indirectly reduced amount is twice to ten- fold. Bioengineering has indirect effectiveness of detaining solid materials by means of increasing vegetation coverage, reducing surface runoff, reducing runoff erosion and improving soil structure. Because of increasing 19%-60% vegetation coverage in 12 debris flow gully basin, the amount of debris flow solid materials indirectly reduces by 4.7 % -34.6 %. For example, the bioengineering of the Heisha river basin in the Xichang City have received a significant effect. The vegetation coverage of this area increases by 60%, and the highest average value of erosion modulus is 9000 t/（km^2· a）, and the erosion type changes from extremely strong to a mild, and the solid materials reduce by 31. 1% （5.894×10^6 m^3）.
出处
《成都理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2013年第1期50-58,共9页
Journal of Chengdu University of Technology: Science & Technology Edition
基金
“十二五”国家科技支撑项目(2011BAK12B02)
关键词
西南山区
泥石流
拦挡工程
生物工程
效益
southwest
mountain area
China
debris flow
geotechnical engineering
bioengineering
benefit
