三峡库区奉节库岸崩坡积物旋喷改性试验研究

Jet grouting improvement on rockfall deposit at Fengjie Shore of the Three Gorges Reservoir

利用高压泥浆泵将纯水泥浆以高速喷射流切割周围松散岩土体,使水泥浆与岩土体搅拌混合,达到改良岩土体性质提高其强度的目的。试验表明,通过高压旋喷注浆对崩积体地层进行改性技术试验后,岩土体工程力学性能有较大提高,旋喷固结体抗压强度平均值为1 99MPa,远远高于岩土体强度;旋喷固结体具有稳定的加固效果并有较好的耐久、耐侵蚀性能。声波测试显示灌浆孔周围动弹模量有明显提高。微观分析表明,加固体的抗崩解性能强,有一定的化学稳定性。但旋喷固结体抗剪性能较差,微孔隙还比较发育,设计时应扬长避短,可考虑在浆液中添加适量的补强、抗蚀成分(石膏等),以进一步提高桩的抗剪强度和抵抗化学侵蚀的能力。高压旋喷注浆能适用于三峡库区内松散堆积层工程地质性质改良,主要用于增加地基强度、增加土的摩擦力及固着力、防止洪水冲刷、降低土的含水量和防渗帷幕等工程。

The shore change will become an urgent problem of engineering geology in the Three Georges Reservoir area. Lots of tech, such as, steel concert pile and plate, geotextile, rock retaining wall and plate, etc., have or are being applied to embankment of the shore. A new result is illustrated that rockfall deposit property is improved through jet grouting at the Fengjie Site. The results show that the means pressure strength of the grouted deposit is 1.99MPa, much greater than normal deposit, and its duration and erosion-resisting is better. The sonic logging detects the wave velocity and dynamic elastic modulus is obviously rising. The grouting mass diameter is over 650～750mm with 75mm diameter of borehole. The analysis shows the structure and component are stable and the slaking durability is excellent.