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小直径荷载板试验(简称P.B.T),是属于野外原位试验中的一种快速评价地基荷载强度的方法。由于这种荷载试验加载的锚定反力易于获得,并能够在较短的时间内,一般只要一至两小时,就能方便而迅速地获取地基土体承受荷载后的变形情况,进而估算地基的承载力密实度。所以,一些发达国家在修建飞机场跑道、公路、铁路工程中,被广泛地用来做土质调查、路基填土压实控制的常规检测手段,并日臻完善,纳入国家标准。在加载形式上,由单循环荷载,发展到多循环荷载,静—动组合加载,以及偏心加载等。但由于这种荷载试验采用的承压板面积较小,致使影响试验精度的因素增多;如果对仪器设备使用不当或忽略试验的条件,则往往得不到预期效果,甚至会做出错误判断。为此,研究与探讨荷载板试验的检测精度和应用时各种临界条件,是很有意义的。 1983～1986年,伊拉克修建了一条时速250公里的高速铁路,采用这种方法控制路基填土压实质量,取得了较好的效果。在这项工程中,我国派出了铁路技术咨询专家组,会同联邦德国铁路咨询公司,担任该工程的施工技术监察工作。笔者在这段工作期间,通过对一些
Small-diameter load plate test (referred to as P.B.T), is a field test in situ a rapid assessment of the method of load-bearing strength. Because this kind of load test loads the anchoring reaction force to be easily obtained, and in a short period of time, usually only takes one to two hours, the deformation of the foundation soil subjected to load can be conveniently and quickly obtained, Bearing capacity density. Therefore, some developed countries are widely used to construct routine tests of earthwork surveys and embankment compaction control in the construction of airport runways, highways and railway projects, and are becoming more sophisticated and incorporated into national standards. In the form of loading, from a single cycle load, the development of multi-cycle load, static-dynamic load combination, and eccentric loading. However, due to the small bearing plate area used in this load test, the factors that affect the test accuracy increase. If the equipment is improperly used or the test conditions are neglected, the expected results are often not obtained, and even misjudgment will be made. Therefore, it is significant to study and discuss the testing precision of load plate test and various critical conditions in application. From 1983 to 1986, Iraq built a 250 km-per-hour high-speed railway and achieved good results by using this method to control the compaction quality of subgrade fill. In this project, China dispatched a group of experts on railway technical advice and worked with the Federal Railway Consulting Company in Germany to supervise the construction technology of the project. The author during this period of work, through to some