藏东南地区冰碛物斜坡钢花管注浆加固试验研究

Reinforcement of the moraine slope with steel screen pipe grouting

摘要:

本文以藏东南地区帕隆藏布流域冰碛物斜坡为例，针对其架空结构较多、固结程度欠佳的特点，提出钢花管注浆加固技术。通过15个注浆孔现场注浆、现场开挖、取样测试等，探讨其施工工艺及加固效果，并结合FLAC3D数值模拟，进一步阐明其加固机理及设计方法。研究结果表明，冰碛物浅表层注浆有效加固半径为20~55 cm，浆液扩展路径与架空结构展布息息相关；注浆加固后土体粘聚力、内摩擦角、压缩模量均得到改善，竖直渗透系数变小；其注浆压力宜采用0.5~1.0 MPa；水灰比宜选用2、1；注浆孔间距与有效加固半径的比值不宜大于8。通过现场试验，形成一套基于3.5 m³空压机、YT28型凿岩机、空心自钻式锚杆及气动式注浆机的花管注浆工艺，轻便快捷，施工效率高，尤其适用于交通不便、施工条件差的情形。

Abstract:

There are a large number of glacier relics in Southeastern Tibet， forming a large number of loose accumulations， which are prone to disasters. There are many voids in the moraines， and the structures are unstable. The technology of grouting reinforcement by steel screen pipe for moraines was studied with discussion of the construction technologies， the reinforcement mechanism， as well as the design method. The numerical simulation was also implemented. The field tests were performed， and the results showed that the effective reinforcement radius of shallow surface grouting of moraine is 20~55cm； the soil cohesion， internal friction angle and compression modulus improved after grouting reinforcement； the vertical permeability coefficient of the soil becomes smaller； the preferred grouting pressure is 0.5 to1.0MPa， the water/cement ratio 2、1， the ratio of the grouting hole spacing to the effective reinforcement radius not greater than 8. Through field tests， a screen pipe grouting process has been formed on the basis of the 3.5 cubic air compressor， YT28 rock drill， hollow self-drilling bolt and pneumatic grouting machine， which is suitable for inconvenient traffic and poor construction conditions.