The DMPe Borehole or Flexible Dilatometer Equipment, also known as a rock pressuremeter, is designed for in-situ determination of the deformation modulus of rock masses in boreholes with diameters of 96mm or 101mm.
The DMPe Dilatometer consists of a probe with a metal central body. Within the probe:
- It features an inflatable membrane (rubber casing) equipped with three pairs of metallic tips arranged at 120° intervals.
- It includes a discrete spring ring and a double-conical membrane holding system.
- Three pairs of inductive displacement sensors, each with two measurement points.
- A pressure sensor for measuring pressure within the probe.
- It also includes a sediment collector.
The probe is read using the D/P BOX Readout, which operates with an Android tablet. A special application allows for the configuration of tests and calibrations, real-time display of test results and graphs, and data recording.
The dilatometer probe is designed to be lowered into the borehole using a set of steel rods. Nitrogen compressed dry gas is used to pressurize the probe.
The borehole dilatometer test is conducted based on the principle of gradually loading the rock with pressure steps and measuring the resulting circumferential deformation.