弱膨胀岩注浆前后干湿变形特性试验研究

An Experimental Study of the Pre-Grouting and Post-Grouting Deformation Properties of Weak Swelling Rock

以宝兰铁路郭家镇第三系泥岩(弱膨胀岩)隧道仰拱遇水隆起病害为工程依托,采用干湿循环变形测量装置,分别对现场所取的原状土样和经注浆处理后的土样进行了室内浸水及干燥试验,以研究其膨胀机理,为隧道施工及质量控制提供技术支持。对比分析试验结果得到:两种试样浸水后,都会产生一定程度的膨胀变形,且最终均趋于稳定,但发现原状试样发生的变形量较大、达到10.52mm,而经注浆作用后的试样,其膨胀变形量较前者明显减小、仅为4.11mm;干燥作用下,原状试样较注浆试样的收缩量也明显。可见,膨胀岩具有遇水膨胀、失水收缩的特性,且膨胀特性更为明显,而注浆能够达到强化膨胀岩内部结构、抵抗膨胀和干缩作用的目的。

With the disease of the inverted arch of the Guojiazhen Tunnel of the Baoji-Lanzhou Railway made of the 3rd-system mudstone（weak swelling rock）,which uplifts when encountering underground water,as the engineering background,a new dry-wet cycling instrument is used to conduct laboratory soaking and drying tests in both the original soil sample taken from the site and the slip-casting-treated soil sample to study the expanding mechanism of them so as to provide technical support for tunneling construction and quality control.Through comparing the test results it is found that both the samples will show a certain amount of expansive deformation after being soaked,and finally tend to be stable.However,it is found that the deformation of the undisturbed sample is greater,up to 10.52 mm,while the expansive deformation of the post-grouting specimen is obviously less than the former,only 4.11 mm.The shrinkage of the undisturbed specimen is also obvious in the drying process.It is thus readily seen that expansive rock has the property of expanding when soaked with water and shrinking when dried,and its expansive property is very remarkable.It is also obvious that grouting can achieve the aims of strengthening the internal structure of expansive rock,and resisting the expanding and shrinking action.