Monitoring

Support before, during and after construction

Our Monitoring department can give you the necessary support during the preparation and realization of your geotechnical project. Risks of possible damage and nuisance are minimized during the entire process.

Acoustic measurement of concrete piles

Acoustic measurements of concrete piles is a fast and economic way to test the integrity of piles.

For the acoustic testing of concrete piles a plastic hammer is used to create an axial compression wave in the pile. Cracks or weaknesses are identified from the reflection of this signal and registered with the field computer. The acoustic measurements are reported to the customer within 24 hours.

Groundwater level monitoring

For carrying out groundwater level measurements and monitoring the groundwater (quantity and quality), monitoring wells are placed in the vicinity of the test location. These monitoring wells are used to carry out groundwater tests and to take groundwater samples.

In urban areas we can create and manage a monitoring well network in order to clarify problems with groundwater and surface water. Based on the data our geohydrologists provide consultancy on the nature of water problems and the possibilities for measures to be taken to reduce or prevent these problems.

Plate bearing test

In order to prevent subsidence of structures, the bottom layers of a hardening must have a good load-bearing capacity. In order to check the load-bearing capacity of the lower layers, a plate bearing test can be carried out.

A plate bearing test is frequently used because it produces immediate results. We have extensive experience in conducting plate bearing tests for checking sandpits, slag and other surfacing materials.

Vibration tests

Damage can be caused to existing built-up areas when pile driving, earthwork or demolition work is being carried out or in areas where there is a lot of heavy traffic. We have refined equipment for measuring vibration and have the necessary knowledge and experience to make judgements about the permissibility of the level and nature of the vibrations.

Once the vibration tests have been carried out a report is drawn up setting out a description of the tests and judgements on the likelihood of damage being caused to adjacent structures.

Automatic settlement plate

With an automatic settlement plate settlements of earthworks can be measured continuously and remotely. We have developed a data panel (www.wepgis.nl) in which the measurement data is continuously presented online. With this data panel the measurements can be followed and downloaded by third parties if permission has been granted.

Settlements are geotechnically closely linked with pore water pressures. Therefore, automatic settlement plates are often used in combination with water pressure data loggers and sand altimeters. These additional measurements can be accessed via www.wepgis.nl.

Precision levelling

Precision levelling can be used to determine the presence of settlements. Before commencement of the pile driving, earthwork or demolition work, height measurement pegs are installed in adjacent plots of land and the 'baseline situation' is registered.

Repeat measurements may determine any settlements. During construction, changes in the implementation methodology may be proposed based on these measurements. By performing precision levelling we can also determine that no direct settlements have occurred during a building process (or construction phase).

Thermal conductivity measurements

By means of thermal conductivity measurements the thermal conductivity of the substrate can be determined. This is particularly important for the dimensioning of high-voltage and transport lines.

The heat-conducting properties of the substrate may vary greatly locally depending on the composition and packing of the soil layers and the medium in which the space between the soil particles is filled. The properties can be determined in the field (up to 1.5 m depth) but also from soil samples in a laboratory.

Crack measurements

Due to various causes cracks can occur in façades and floors. These existing cracks can be increased, for example, by groundwater level reductions, construction activities or foundation defects. By performing crack measurements it is possible to monitor the cracks.

A crack monitor is placed on the crack and consists of two parts, each of which is attached to one side of a crack. The application of crack measurements over a period of time can determine objectively whether cracks may or may not become larger (active).

Gradient measurements

Horizontal displacements in the subsurface can lead to damage to buildings and infrastructures such as dikes, roads and transport pipelines. Horizontal displacements are particularly related to earth works.

These displacements can be determined by regularly performing accurate gradient measurements in vertical measuring tubes. Timely and adequate anticipation of the results of the gradient measurements can often prevent significant damage.

Deformation measurements

Many construction projects are carried out in the immediate vicinity of existing buildings. To avoid damage, measurement points are applied to these objects, which are regularly measured. These deformation measurements are usually performed manually. If, in addition to vertical, horizontal deformations (x-y-z) are to be measured, this is done with a Total Station.

For an automated deformation measurement, a Total Station is set up once and automatically performs the measurements over the duration of the project. We have developed a data panel (www.wepgis.nl) in which the measurement data is continuously presented online.