DATA SSH
DATA
HEEEETT
Borehole Rod Extensometer
GEO-XB RANGE
Applications
Protective Cap
Displacement Sensors
Reference Head
Rods & Sleeves
For the measurement of:
of dam abutments
~ Deformation
& foundations
movement around
~ Ground
tunnels & mines
movement behind
~ Ground
retaining walls & sheet piles
movement within open
~ Ground
cast mines
~ Deformation of mine pillars
in roofs of
~ Fracturing
underground caverns
~ Deformation of concrete piles
& heave in soft soil
~ Settlement
excavations
Features
Anchors (Groutable
shown)
The Geosense® GEO-XB rod type extensometer range is used to
measure and locate settlement, displacement and deformation in soil
and rock.
It consists of a reference head and one or more in-hole anchors each
of which is placed at a known depth and connected to the reference
head by either a rigid or flexible rod running inside a sleeve which
keeps the rod de-bonded from the grout.
& easy to install in up~ Quick
hole applications
access & adjustment to
~ Easy
sensors
& electrical
~ Mechanical
combination possible
grout holes in head
~ Integral
make grouting easy
~ Accurate & reliable
vw
VIBRATING WIRE
TECHNOLOGY
As the soil or rock deforms the distances between the in-hole anchors
change as do the distances between the individual in-hole anchors and
the reference head. The magnitude, distribution, rate and acceleration
of deformation can be accurately measured at the reference head.
The GEO-XB rod type extensometer range is available in a wide range
of reference heads, anchors, rods and measuring sensors.
A division of
Marton Geotechnical Services Ltd
Nova House, Rougham Industrial Estate, Rougham, Bury St Edmunds, Suffolk IP30 9ND, England
www.mgsgeosense.co.uk e info@mgsgeosense.co.uk t +44(0)1359 270457 f +44(0)1359 272860
DATA S H E E T
Borehole Rod Extensometer
GEO-XB RANGE
Measurement
Measurement is available in the following options:
~ Mechanical
Reading is carried out using a dial indicator or depth micrometer.
~ Electric
Reading is carried out using an electrical sensor.
~ Combination
Both electric and mechnical readings.
Reference Heads
Reference heads are available in the following types:
MECHANICAL
Can be used where there is easy access to the extensometer and automatic readings are not required.
GXB-M : Mechanical
The rod(s) terminate in the reference head block where manual
readings are taken with a depth micrometer. The head is normally
installed more or less flush with the top of the borehole.
ELECTRIC
Used when access to the reference head is difficult or where continuous monitoring is required.The
rod(s) are connected to an electrical sensor. Movements are measured by converting the signals to a
measurement of length change.
GXB-ES: Electric Sensor, Standard 1-Part Head
A one-part head where the rods connect to the sensors which are
mounted on a moveable internal flange within the head and protected
by a one piece outer cover. The head is mounted external to the
borehole with all the sensors and rod connections located entirely
within the head itself. All connections & sensors can be completely
accessed post installation by removing the outer cover. The length of
the head will depend on the range of the sensor.
A division of
Marton Geotechnical Services Ltd
Nova House, Rougham Industrial Estate, Rougham, Bury St Edmunds, Suffolk IP30 9ND, England
www.mgsgeosense.co.uk e info@mgsgeosense.co.uk t +44(0)1359 270457 f +44(0)1359 272860
DATA SSH
DATA
HEEEETT
Borehole Rod Extensometer
GEO-XB RANGE
GXB-EL: Electric Sensor, Low Profile 2-Part Head
A two-part head with a lower section and an upper section divided by
a fixed intermediate flange and has a lower and upper outer cover. The
rod connections and the lower part of the sensors are located within
the lower section which is installed within the borehole. The top of the
sensors located in the upper section are external to the borehole and
adjustment can be done by removing the upper outer cover. The
length of the upper section will depend on the range of the sensor but
provides a lower profile than the GXB-ES.
COMBINATION
GXB-ES-M: Electric Sensor plus Mechanical, Standard 1-Part
Head
GXB-EL-M: Electric Sensor plus Mechanical, Low Profile 2-Part
Head
All features of the standard version with the additional of a mechanical
system which means electrical sensors can be removed, checked
and/or replaced; in the event of an electrical sensor fail data can still
be taken manually; a manual check is always available to check any
long term drift of electrical sensors
All GEO-XB reference heads can be use with either flexible or rigid
rods & sleeves (see table below).
Specifications - Reference Heads
TYPE
REFERENCE HEAD TYPE
MEASUREMENT SENSOR
ROD TYPE
NO OF POINTS
GXB-M-R
Mechanical
Rod
Rigid
1-8
GXB-M-F
Mechanical
Rod
Flexible
1-8
GXB-ES-VW-R
Electric standard
Vibrating wire
Rigid
2-6
GXB-ES-VW-F
Electric standard
Vibrating wire
Flexible
2-6
GXB-ES-VW-R
Electric low profile
Vibrating wire
Rigid
2-6
GXB-EL-VW-F
Electric low profile
Vibrating wire
Flexible
2-6
GXB-ES-LP-R
Electric standard
Linear potentiometer
Rigid
2-6
GXB-ES-LP-F
Electric standard
Linear potentiometer
Flexible
2-6
GXB-ES-M-VW-R
Electric standard + mechanical
Vibrating wire + rod
Rigid
2-6
GXB-ES-M-VW-F
Electric standard + mechanical
Vibrating wire + rod
Flexible
2-6
GXB-EL-M-VW-R
Electric low profile + mechanical
Vibrating wire + rod
Rigid
2-6
GXB-EL-M-VW-F
Electric low profile + mechanical
Vibrating wire + rod
Flexible
2-6
GXB-ES-M-LP-R
Electric standard + mechanical
Linear potentiometer-rod
Rigid
2-6
GXB-ES-M-LP-F
Electric standard + mechanical
Linear potentiometer-rod
Flexible
2-6
Other options available on request
A division of
Marton Geotechnical Services Ltd
Nova House, Rougham Industrial Estate, Rougham, Bury St Edmunds, Suffolk IP30 9ND, England
www.mgsgeosense.co.uk e info@mgsgeosense.co.uk t +44(0)1359 270457 f +44(0)1359 272860
V1.1 01/212
DATA S H E E T
Borehole Rod Extensometer
GEO-XB RANGE
E l e c t r i c D i s p l a c e m e n t S e n s o rs
The following sensor types are available:
~ Vibrating wire displacement gauge
~ Linear Potentiometer
~ Linear Variable Differential Transformer
S p e c i f i c a t i o n s - E l e c t r i c D i s p l a c e m e n t S e n s o rs
DESCRIPTION
RANGES
Mechanical
0 - 150mm
Vibrating Wire
5,12.5, 25, 50, 75, 100, 150, 200, 300mm
Linear potentiometer
10, 20, 30, 50, 125,100,150mm
LVDT
25, 50, 75, 100, 150mm
Rods
Rods are used to connect the anchors to the reference head and are
available in rigid or flexible form.
Rigid
~
Made from stainless steel and come in short lengths of 1,2,3 metre
with flush threads. A starter rod is connected to the anchor.
~ Flexible
The glass & carbon fibre rods are a continuous length factory
produced to meet the project requirements.
Specifications - Rods
MATERIAL
DIAMETER
YOUNG’S MODULUS
EXPANSION COEFFICIENT
Stainless steel
6mm
200 GPa
16.0 ppm/°C
Fibreglass
5mm
20 GPa
3.0 ppm/°C
Carbon fibre
5mm
130 GPa
<1.0 ppm/°C
DIAMETER
LENGTHS
MATERIAL
6mm
1, 2, 3m
Stainless steel
5mm
1, 2, 3m, continuous
Fibreglass
5mm
1, 2, 3m, continuous
Carbon fibre
S l e ev e s
A division of
Marton Geotechnical Services Ltd
Nova House, Rougham Industrial Estate, Rougham, Bury St Edmunds, Suffolk IP30 9ND, England
www.mgsgeosense.co.uk e info@mgsgeosense.co.uk t +44(0)1359 270457 f +44(0)1359 272860
V1.1 01/212
DATA SSH
DATA
HEEEETT
Borehole Rod Extensometer
GEO-XB RANGE
S l e ev e s
Sleeves allow the rods to move freely and prevents bonding of the rod
and grout. They are available in the following options:
~ Rigid
Made from rigid PVC with flush threaded or push fit joints. A starter
sleeve is connected to the anchor.
~ Flexible
Made from flexible nylon available in short lengths with external
couplers which can be used with the rigid rods or a continuous length
for use with the flexible rods.
Specifications - Sleeves
1/4”x 1m PVC rigid sleeve FT
10mm x 1m flexible sleeve
1/4”x 2m PVC rigid sleeve FT
10mm x 2m flexible sleeve
1/4”x 3m PVC rigid sleeve FT
10mm x 3m flexible sleeve
1/4” starter sleeve
10mm coupler
1/4” sleeve spacer
A n c h o rs
Anchors are located at various depths within the borehole and connected to the rods. The choice of
anchor will depend on the surrounding ground and are available in the following types:
~ Groutable (Image 1)
Generally used in downward-directed boreholes. Used in compact
rock and non-cohesive soils. Installed in the borehole and then
grouted.
~ Hydraulic (2)
Borros Type for use in soft soils and clays, especially in augered
boreholes.
Drives prongs into the soil using hydraulic pump. Available in single or
double options.
1
2
3
4
~ Snap ring (3)
For use in hard or competent rock. Anchors are pushed to the
required depth and then a cord is pulled to remove the locking pin.
Retaining rings on each anchor snap outward and grip the borehole.
Particularly useful in upward directed boreholes.
Packer type (4)
~
Used in soft soil conditions, granular materials and are used typically
in up-hole installations. Inflated with cement by an injection tube.
Specifications follow.
A division of
Marton Geotechnical Services Ltd
Nova House, Rougham Industrial Estate, Rougham, Bury St Edmunds, Suffolk IP30 9ND, England
www.mgsgeosense.co.uk e info@mgsgeosense.co.uk t +44(0)1359 270457 f +44(0)1359 272860
DATA S H E E T
Borehole Rod Extensometer
GEO-XB RANGE
Specifications - Anchors
DESCRIPTION
CONNECTION
16mm Groutable anchor
Rigid sleeve
16mm Groutable anchor
Flexible sleeve
16mm Groutable anchor BZP
Rigid sleeve
16mm Groutable anchor BZP
Flexible sleeve
Single hydraulic Borros type
Rigid sleeve
Double Borros type
Rigid sleeve
Snap ring anchor*
Rigid sleeve
Snap ring anchor*
Flexible sleeve
Packer anchor
Rigid sleeve
Packer anchor
Flexible sleeve
1
2
* Diameter to suit individual borehole
Accessories
Installation kit
16mm x 30m coil grout tubing
Hydraulic pump & hose
Readouts
0 - 150mm digital depth gauge (Pic 2)
VW 2106 readout (Pic 1)
Portable Potentiometer Readout
Geologger Automatic Data Acquisition
O rd e r i n g I n fo r m a t i o n
~ Reference head type
~ Sensor type, range and quantity
~ Anchor type & quantity
~ Distance between anchors
~ Rod type & quantity
~ Readout type
A division of
Marton Geotechnical Services Ltd
Nova House, Rougham Industrial Estate, Rougham, Bury St Edmunds, Suffolk IP30 9ND, England
www.mgsgeosense.co.uk e info@mgsgeosense.co.uk t +44(0)1359 270457 f +44(0)1359 272860
V1.0 01/2012