Geotechnical Instrumentation

GeoZone GeoServices officially represent SISGeo Geotechnical Instrumentation in Southern Africa and as such are well placed to supply a wide range of instruments for any civils or mining project.  We also have the capacity to design instrumentation programmes from scratch, carry out the installation and collect and analyse the data if need be.

SISGEO Geotechnical Instruments, based in Milan, Italy has an operation comprising more than 1200 square metres of laboratories, production facilities and warehousing with an associated technical staff to design, build, calibrate, sell and install their systems. Sisgeo manufactures all of their instruments, only importing GPRS technology for on-site monitoring of their equipment.  The company is a leading designer and manufacturer of a wide selection of instruments for monitoring geotechnical and civil engineering projects and has an ISO 9001 Certification which forms the basis of their continuous improvements and quality control programmes.

So why instrument?

Well, to spell things out, here are the reasons why we should instrument our civil engineering and mining projects:
1)      Benefits During Design
1.1    Definition of Initial Site Conditions

Instrumentation may be used to assist in assessing the in situ geotechnical conditions during the design phase.  A simple example is the installation of piezometers to monitor groundwater levels and hydraulic head.  More complex examples include assessments of in situ stress and deformability conditions for design of tunnel linings or large underground excavations.  By understanding the geotechnical conditions, a more focussed and optimal design can be arrived at.

1.2  Proof Testing
All designs have inherent uncertainties and to a large extent these are circumvented by using conservative design parameters and that fantastic fudge factor called the Factor of Safety.  However if we were to reduce the degree of uncertainty in a design by carrying out a proof test, then the advantages thereof need not be spelled out.  A proof test will include observations on behaviour, and may well include instrumentation.  A proof test allows the designer to choose an economical design over an ultra conservative one when ground conditions are not fully understood or construction methods are uncertain.

1.3  Fact Finding in a Crisis Situation
Should a crisis arise, the nature of the problem needs to be defined so that remedial measures can be implemented, and instrumentation, if correctly installed, can play a crucial role in this.

2)      Benefits during Construction

These include:

*        Improvements in safety for the construction workers and the public
*        Reduce construction costs
*        Control construction procedures
*        Provide legal protection
*        Provide data for measurement of quantities
*        Enhance public relations
*        Advance the state of the art, and finally
*        We get to sleep well at night.

Safety of course is paramount and instrumentation can provide the needed safeguards.  In addition there is a need to monitor the effects of construction on neighbouring structures.  Use of instrumentation for safety monitoring is routine during excavations for builds, tunnels and highways.

SISGEO manufactures and installs the following range of instruments:

*        Pressure Transducers
*        Inclinometers
*        Settlement Gauges
*        Pressure and Load Cells
*        Extensometers & Joint meters
*        Pendulums & Readouts
*        Strain Gauges & Thermometers
*        Readouts, Dataloggers & Accessories

We also have experience of installing Golders RMT dual height tell tales in mines to monitor movement in the roof of excavations.  These instruments are relatively cheap and easy to install and are extremely useful for monitoring stability in temporary excavations.  The beauty of this system lies in their easily understood, readily readable tell-tales.  Any movement within the roof is immediately registered on the mm scale on the tell tale, and larger movements move the tell tales into different coloured zones – intuitively marked green, yellow and red.

Major Projects Completed to Date:

  • Gautrain Remediation Project
  • Nacala Dam Instrumentation Design and Installation
  • St Helena Airport Design and Installation of Instrumenation
  • Metolong Dam, Lesotho
  • Koffiefontein Diamond Mine Tell Tale Installation
  • Booysendal Tailings Dam
  • Huguenot Tunnel Convergence Extensometers

Projects in the Pipeline:

  • Upgrade of Katse and Mohale Dam Instrumentation
  • Raising of the ClanWilliam Dam, Western Cape
  • Installation of Multipoint Extensometers at the Growthpoint development, Centurion
  • Installation and monitoring of fills in bridge abutments, Western Cape