土石混合土层注浆固结体崩解特性研究

Research on Disintegration Characteristics of Soil⁃rock Mixed Grouting Concretion Body

为研究元阳老虎嘴滑坡区梯田土石混合体注浆后固结体崩解特性,本文对元阳梯田土石混合体进行室内模型注浆后取样养护,再进行室内干湿循环崩解试验分析。结果表明:注浆固结体的崩解主要是未受浆液胶结或胶结弱的石块或土颗粒的崩解损失,且距离注浆孔越远,崩解掉落损失的土块直径越大;固结体前3次崩解的崩解速度最快,之后崩解速度变缓;注浆压力变大,崩解率会变小,但注浆压力增大幅度仅为0.1 MPa时对固结体的崩解改善作用并不是很明显;存在一个介于0.8~1.0之间的临界水灰比,当水灰比小于临界值时,同一压力下固结体崩解率随水灰比增大而减小,反之当水灰比大于临界值时,同一压力下固结体崩解率随水灰比增大而增大;对于注浆压力大的注浆固结体,养护时间变大能改善固结体崩解性,注浆压力小时养护时间对崩解性无影响。建议此次工程选择注浆压力0.45 MPa、水灰比0.8的注浆参数,固结体抗崩解性最好。

In order to study the characteristics of concretion body disintegration after grouting of soil⁃rock mixture in the terraced field of Huzui landslide area in Yuanyang,the indoor model of soil⁃rock mixture in Yuanyang terraced field was carried out after sampling and maintenance,and then the indoor dry⁃wet cycle disintegration test was conducted.The results show that the disintegration of grouting concretion body is mainly caused by the disintegration loss of stones or soil particles unconsolidated or weakly consolidated by grout,and the farther the distance from the grouting hole,the larger the diameter of the soil lost by disintegration.The disintegration speed of consolidation body is the fastest in the first three times of disintegration,and the disintegration speed becomes slow in the rear.When the grouting pressure increases,the disintegration rate decreases.However,when the grouting pressure increases only by 0.1 MPa,the improvement effect on the disintegration of the concretion body is not very great.There is a critical water⁃cement ratio between 0.8 and 1.0.When the water⁃cement ratio is less than the critical value,the disintegration rate of concretion body under the same pressure decreases with the increase of water⁃cement ratio.On the contrary,when the water⁃cement ratio is greater than the critical value,the disintegration rate of concretion body under the same pressure increases with the increase of water⁃cement ratio.For the grouting concretion body with high grouting pressure,the increasing of curing time can improve the disintegration of the concretion body,and the curing time has no effect on the disintegration when the grouting pressure is small.It is suggested that the grouting parameters of 0.45 MPa grouting pressure and 0.8 water⁃cement ratio should be selected for this project,which has the best disintegration resistance of the concretion body.