A solution to concurrent measurement of the normal and tangential earth pressure in model tests

摘要

In numerous projects in the field of earth-pressure research, the distribution of earth pressure is of interest, as well as the force described by value, location, and direction. Often the tests remain limited to a puncti-form measurement of earth pressure, and in many cases only the earth-pressure component acting normally to the surface is measured. Thus, assumptions have to be made for the direction of action. A new type of load cell has been developed at the TU Dresden's Institute of Geotechnical Engineering. This type is capable of concurrently measuring normal and tangential earth pressure and includes larger parts of a surface. It is based on a simple, statically determinate system. The principle construction of the load cells will be presented, including the necessary force transducers. The transducers work on the basis of strain-measurement technology. They have been developed at the Institute for different force levels. For this reason, the load cells may be adapted to the estimated stress level in the model test. With the side-by-side arrangement of these load cells, it becomes possible to determine the distribution of earth pressure and its inclination over the height of the wall. Therefore, the entire surface of the wall or parts of it may be covered. The measurement principle proved the functionality in several completed research projects at the Institute. Some of the applications, together with the adaption to the special task, will be also presented. Typical features, application possibilities, and limits will be discussed.