土坝在设计和运行中防治白蚁危害的研究

以往在水库大坝发生白蚁危害病情后,方采取工程措施进行除险加固。为把白蚁控制在危害之前,本文结合工程典型实例,根据气候、土壤、植被等建坝外部环境条件和白蚁生存需具备的土、水、食料基本因素,考虑白蚁具有喜温好湿、畏光避风、蔓延等生物特性,通过填筑坝料土质分析,研究了水库蓄水坝体浸润性、坝土级配及湿度与白蚁生存之间的关系,并提出相应对策以达到防患于未然。结果表明,坝体结构设计时,通过截断白蚁吸水水源,增加坝体干燥区,缩限白蚁生存空间;通过调整坝料级配,防止白蚁筑巢;合理采用护坡,切断白蚁食源。同时,结合水库运行管理,采取"预防为主,综合防治"的措施,使坝体周边一定范围内成为无蚁区,防止白蚁蔓延至坝,维护水库大坝的安全。

Research of preventing termite damage during design and operation of the earth dam

Previously, the engineering measures of danger elimination and consolidation were taken only after the termite damage illness of the reservoir dam happened. In order to control the damage of termite effectively, the corresponding treatments are studied by typical project cases, in which the external environment conditions, such as climate, soil and vegetation, the basic survival factors of termite, such as soil, water and food, the biological characteristics of termite, such as thermophilic, hygrophilous, photophobia, shelter and spread are considered. Through the analysis of the relation between the properties of soil, the wettability of dam,the graduation and humidity of soil and the survival of termite,the corresponding treatments are proposed to prevent the damage of termite. The results show that, the water source of termite can be blocked by optimizing design of dam, the living space of termite can be reduced by increasing the dry area of dam, the nesting of termite can be prevent by adjustment of gradation of soil, and the food source of termite can be cut off by the proper design of slope protection. Meanwhile,by combining the operation management of reservoir with the policy of "Prevention first, Comprehensive prevention and control", no ants area can be formed within a certain range of dam to prevent the spread of termite to the dam. The results have practical significance for the safety of dam.