卵石层钻进和预引孔直接静探实践

Analysis of Drilling in Cobble Layer and Direct Static Sounding in Pre-guide Hole

要获取卵石、漂石的物理力学性质指标,就必须查明卵石的密实度,颗粒大小、颗粒骨架分布、含量以及充填物的含量。而施工效率低,劳动强度大,成本高是卵石、漂石钻孔施工中的的主要问题。用动力触探判定卵石层的密度有一定的局限性,当打到卵石顶面时击数很高,打到卵石缝内击数又很低,动弹数据离散性大,必须和《建筑工程地质勘探与取样技术规程》(JGJ/T 87—2012)附录表G.0.6定性判定相结合,才能使确定的密实度更客观。静力触探往往无法直接穿越密实的砂层,获取其下部的细粒土静力触探指标也是个工程中经常遇到的问题。根据几个不同的场地岩土工程勘探实践对上述问题进行了有益探索。

To get the physical and mechanical properties of cobble and boulder, you should first find out the compact- ness, grain size, distribution patterns, contents, and the fillings content. Now, lower construction efficiency, great labour in- tensity and high cost are the main problems in drilling. Meanwhile, there is a limitation that using dynamic sounding to judge the density of cobble, because it is much higher when drilling the surface of cobble, and lower when drilling the fracture of cob- ble. Considered with 〈〈Technical specification for engineering geological prospecting and sampling of constructions））JGJ/T 87-- 2012 attached table G. 0. 6, the acquired compactness will be more objective. Static sounding generally cannot cross tight grav- els, so how to get the static sounding data below them is a difficult problem in our work. Based on several different geotechnical engineering exploration practices, this paper discussed the solutions for the above mentioned problems.