泥岩地基及嵌岩灌注桩的承载特性试验

红土崖组(KwH)泥岩是一种分布于青岛地区的白垩系王氏群泥岩,是一种非典型的黏土岩,其透水性弱,具有一定的膨胀特性。为研究泥岩的物理力学性质、变形特性及嵌入泥岩中灌注桩的承载特性,以红土崖组(KwH)泥岩为试验对象,在青岛某地区开展了泥岩常规物理力学试验、泥岩地基及泥岩地基中嵌岩灌注桩的静载荷试验。试验结果表明,红土崖组(KwH)泥岩含砂,吸水膨胀率较小,是一种非膨胀性岩；全风化及强风化泥岩地基的P-s曲线基本呈缓变型；而中风化泥岩地基在破坏时发生了压裂及隆起,P-s曲线呈陡降型,而且变异性较大。该场地泥岩地基中灌注桩分别加载至10800 kN、12960 kN,试桩均未发生破坏,嵌岩灌注桩的桩侧摩阻力和桩端阻力均未充分发挥；中风化泥岩的承载力较高,可作为桩基理想的持力层；泥岩具有初始损伤特性,且随着应力水平的提高其损伤逐渐加剧。研究成果对青岛地区泥岩地基中的工程建设具有参考价值。

Experimental study on bearing characteristics of mudstone foundation and pile embedded in mudstone

KwH mudstone is a kind of cretaceous Wang group mudstone distributed in Qingdao area. It is a kind of atypical clay rock with weak permeability and certain swelling characteristics. In order to study the physical and mechanical properties and deformation characteristics of mudstone and bearing characteristics of cast-in-place piles embedded in mudstone, conventional physical and mechanical tests of mudstone, static load tests of mudstone foundation and cast-in-place piles embedded in mudstone foundation were carried out in a certain area of Qingdao, taking KwH mudstone as test object. The results show that the KwH mudstone is a kind of non-expansive rock with sand content and low water absorption and expansion rate. The P-s curve of mudstone foundation with full weathering and strong weathering basically shows a slow variation type. However, fracturing and uplift occurred during the failure of the moderately weathered mudstone foundation, and the P-s curve showed a steep drop and great variability. In the mudstone foundation of the site, the cast-in-place piles were respectively loaded to 10800 kN and 12960 kN, and the test piles did not damage, and the side friction resistance and tip resistance of rock-socketed cast-in-place piles were not fully exerted. The moderately weathered mudstone has a high bearing capacity and can be used as an ideal bearing layer of pile foundation. Mudstone has initial damage characteristics, and its damage is gradually intensified with the increase of stress level. The research results have reference value for the engineering construction of mudstone foundation in Qingdao area.