淮河大堤土体工程地质特性及采动裂缝研究

淮河下采煤,使地面大堤土体中出现了许多采动裂缝,普遍认为裂缝的存在对大堤与河下采煤安全构成很大威胁。以土体工程地质特性研究为基础,采用试验和力学分析方法,分析论证了大堤土体采动裂缝的形成条件及其发育深度,得出几点结论:1)目前,淮南淮河大堤在粘土堤土体拉应变超过8～12mm/m、砂土堤超过3～5mm/m时,堤体就会出现裂缝;2)土中裂缝发育深度不会超过与土的力学特性有关的某一极限值。目前淮河大堤粘土堤约为4.0m、砂土堤约为2.0m;3)采取粘土注浆、铺设防渗膜等措施处理后,淮河大堤采动裂缝的存在就不会对河下采煤与大堤安全构成威胁。

STUDY ON THE ENGINEERING GEOLOGICAL PROPERTIES OF THE SOIL MASS AND THE MINING CHINK'S FORMING CONDITIONS AND IT'S GROWTH DEPTH OF THE HUAI RIVER LARGE DIKE

There are many chinks in the Huai River Dike as the result of the coal mining under the Huai River. It is consindered generaly that those chinks in the Dike could have a great threat to the security of the Dike and the coal mining under the River. In this paper, the chink's forming condition and it's growth depths were analysed and demonstrated bosed on the study on the soil mass engineering geological properties as well as by the means of testing and mechanics analysis method, several important conclusions obtained show as:1. about the preseat Huai River Dike in Huainan, when the tensile strain of the clay Dike exceeds 8-12mm/m and the sand Dike's exceeds 3-5mm/m,the chinks in the Dike body will arise; 2. the chink's growth depth will not ever exceed a certain limit value, this value deals with the machanical characteristics of the soil mass, at present, the mining chink's limit depth of the Huai River Dike in Huainan is approximatly 4. 0 meters for the clay Dike and 2. 0 meters for the sand Dike; 3. only to adopt clayey grouting and to pave the facing water slope with a kind of unpermeable plastic film and so on measures, the existence of the Dike's chinks will not threaten the security of the coal mining under the River and the Large Dike's self.