Perry Drilling Limited . Geotechnical and Environmental Drillers

• Drill bits, coring equipment, wash drilling equipment, hollow stem augering capabilities, drill rods and casing to allow drilling in all types of geological conditions to the full capacity of each drill rig.

• Subs to allow for thin wall tube sampling.

• Two sets of SPT sampling equipment with split spoon and solid testing capabilities.

Any additional equipment or specialized requests can be readily obtained through the backing of our local hire company and our engineering work shop.

Triple Tube Core Drilling

Perry Drilling operate Triple Tube Wire Line core drilling on all its rigs. We have researched and designed special cutting tips and core catches to provide optimum sample retrieval and minimise core loss. This allows relatively quick advancement of the borehole and provides the client with optimal core recovery in all conditions. It is a proven technique throughout the world and used extensively in all types of exploration drilling and geotechnical drilling. Triple-tube core barrels use a second inner tube (split lengthwise) inside the standard inner tube to retrieve the sample. It is then retracted from within the drill rods via the wire line winch and the core is ejected using the core ejection piston which protects the core from pressurized drilling fluid when the split inner tube, containing the core sample, is pumped out of the standard inner tube. Upon removal, one half of the split tube is lifted off to reveal the undisturbed core sample. The process is then repeated to advance the drill hole.

Insitu Geotechnical Testing

Perry Drilling operates a wide range of insitu testing equipment to supplement our drilling operation. Standard Penetration Testing (SPT), Shear Vane Tests, Thin Wall Push Tubes, Packer Tests, Permeability Tests and Falling Head Tests are regularly conducted during drilling. These tests supplement the samples recovered and the information gathered to provide accurate projections of data for structural and engineering designs.

Instrument Installation

During our extensive Drilling and Cone Penetrometer Testing experience we have installed a wide range of downhole instrumentation. Vibrating wire piezometers in inclined boreholes to 70m, other various depths and configurations in vertical borehloes. Pneumatic piezometers to various depths, simple standpipes and piezometers of differing diameters and depth. Monitoring wells in all types of applications, dewatering monitors, environmental sampling and water table measurements. Inclinometers in a wide range of applications from road slip management to construction zones. We also have the capability of installing horizontal dewatering drainage for road cuttings and house site slip management.

Wash Drilling

Wash drilling is a simple technique using water or a similar drilling fluid to lift the cuttings to the surface while advancing the drill bit down the borehole. Samples can be bagged off at desired intervals during the advancement stage giving an indication of the geology below.

Open Auger Investigation

This technique is often used for relatively shallow boreholes for indicative analysis of the soil structure. It is a relatively quick technique and allows a large number of shallow boreholes to be completed in a short time. The sample retrieved is ideal for indicative geology assessment which provides a better overall picture of the stratigraphy below the surface. Ideal for subdivision investigations where a large number of auger boreholes are required quickly without the intensive labour of hand augering.

Hollow Stem Augering

Hollow Stem Auger drilling was initially the mainstay of Perry Drillings investigations with a large number of environmental sites requesting split spoon sampling with hollow stem augers due to the fact that they do not require a drilling medium such as water in order to operate. Therefore there is no introduction of possible contaminants from a foreign source. The hollow stem augers we operate have the ability to recover split spoon samples and install large diameter monitoring wells. This makes them ideal for environmental sampling in a variety of soil types and conditions.

Percussion (Air) Drilling

Perry Drilling has the capacity to air drill using air hammers of various sizes. A large percentage of the air drilling we conduct is to penetrate rock for instrument installations where wireline coring is not suitable or the client requests percussion drilling.

Cone Penetrometer Testing - CPT & CPTU

Perry Drilling Limited purchased it’s first track mounted Cone Penetrometer Rig in 1998 and has subsequently purchased, it’s 2nd and 3rd Cone Penetrometer Rigs in 2007(track mounted) and 2008 (heliportable). Perry Drilling has the ability to provide CPT rigs that will supply high quality information vital to make cost effective foundation and environmental decisions. The software and soil analysis programs are regularly updated as new developments become available.

CPTask Output

Siesmic CPT testing

To further enhance Perry Drillings status as the leading CPT operator in New Zealand we own and operate a GeoMil ( www.geomil.com )Seismic Cone Penetration Testing (SCPT) system. The SCPT is a very valuable geotechnical tool used in determination of low strain in-situ compression(P) and shear (S) wave velocities. The P-wave and S-wave velocities are directly related to the soil elastic constants of Poisson’s ratio, Shear Modulus, Bulk Modulus and Young’s Modulus.

The seismic CPT acquisition is conducted with a 10cm2 compression CPT(U) cone allowing both CPT data and SCPT data to be collect at the same time. It is designed such that the seismic sensors record the soil profile’s response to low strain seismic disturbances. SCPT testing is conducted using accelerometers for good definition of the frequency spectrum of the recorded signal. To avoid smearing, the GeoMil seismic adapter is equipped with accelerometers (1 Hz - 10 kHz) and not with geophones (typically 1 - 300 Hz).

For quality assessment and proper data analysis, the frequency filtering of data is done after acquisition and not during the recording. The measured values are transferred as voltage signals by means of a cable connected on surface to the "Signal Conditioning System" where CPT data is separated from the seismic data.

The seismic source used generates dominant SH waves (e.g. hammer beam). The hammer beam comprises of applying a hammer blow laterally to the sides of special designed plates fixed to the penetrometer. The hammer beam generates excellent polarised SH wavelets and it is standardly applied in reverse polarity analysis (Baziw, 1988).

The seismic data is then processed by software from Baziw Consulting Engineers ( www.bcengineers.com ). BCE provides both data acquisition and the data reduction, analysis and visualisation software packages.

Accurate in-situ P-wave and S-wave velocity profiles are essential in geotechnical foundation designs. These parameters are used in both Static and Dynamic Soil Analysis. Another important use of estimated shear wave velocities in geotechnical design is in the liquefaction assessment of soils. Since the shear wave velocity is influenced by many of the variables that influence liquefaction (void ratio, soil density, confining stress, stress history, and geologic age), it is an excellent index of liquefaction.

Soil Moisture Probe

The Soil Moisture Probe once again shows Perry Drillings commitment to be at the forefront of technology. Soil moisture, or the volumetric percentage of water in soil, has become an important consideration in the design of environmental remediation processes and agricultural planning, and it is one of the most fundamental factors influencing soil strength. The SMP probe takes advantage of relationship between the soil dielectric constant and moisture, widely known as Topp's Equation. The relationship is not heavily influenced by soil type and resistivity if the dielectric measurement is made above a critical frequency. Soil moisture content is determined by measuring the frequency shift of a high frequency excitation signal as it passes through the soil. Software algorithms then apply Topp's Equation to generate volumetric soil moisture values.

Until now, soil moisture has been determined by time consuming and expensive soil sampling. At best, these methods generate discrete points of information and require many days of field and lab work. Soil Moisture Probe provides real-time, in-situ logs of soil moisture and resistivity without sampling.

CPT Soil Sampling

Perry Drilling operates VERTEK’s Soil Sampler built for retrieval of minimally disturbed soil samples in difficult geologies. The sample barrel with retractable tip is pushed to the desired depth. A lanyard lowered through the push rods then retracts the tip back into the housing. With the tip retracted, the lanyard is removed back to the surface and the Soil Sampler is ready for sampling. Advancing the sampler samples the soil into stainless steel split spoons or there is an option to sample with a plastic sleeve. The sampler and rod string are then retracted, bringing the sample safely to the surface. The sleeve containing the sample core can be removed, examined and logged, or capped and sent to a lab for analysis. Longer samples can be obtained easily by threading multiple sample barrels together. Split sleeves and clear plastic sleeves allow fast, easy visual inspection. The Soil Sampler is easily disassembled for cleaning or decontamination between samples. VERTEK’s Soil Sampler includes a unique core catcher (similar to the catchers in our SPT samplers) designed to retain loose soils that tend to flow out of standard samplers. As the tip is retracted through the sample tube, an O-ring around the tip assembly creates a slight vacuum in the tube above the sample. This vacuum helps to raise and retain the sample in the tube like water held in a straw. The Soil Sampler provides proven reliability in even the most challenging geologies.

SAMPLE SIZE:

DIAMETER: 35mm

LENGTH: 536 mm

CPT Standpipe Installation

The Cone Penetrometer Rig is also effective in installing Standpipe Piezometers to various depths relatively quickly. It is often used to provide a cost effective method of installing numerous standpipes on one site to provide a large number of sample points in environmental projects. It has previously installed 42 Standpipe Piezometers in one day to a depth of six metres with screens and filter sox for an environmental study in nitrate reduction through carbon filters.

Electrical Vane Tester

The Electric Shear Vanes Tester is newly designed and state of the art measuring device. Existing vane testers tend to have a low accuracy and only basic control functions. The Electric Shear Vane Tester is a PLC controlled device with a high precision torque sensor. The testing process and the data acquisition are controlled by electronic software.

With a nominal torque of 100Nm the determination of the undrained shear strength of cohesive soils is relatively easy operation.

The rotational speed can be adjusted from 0.1° per second up to 15° per second, while the sampling rate can be defined by the operator. The logging and control software communicates with the PLC and interacts with the user by an Excel spread sheet. According to the chosen vane dimension the software monitors the actual torsion and limits the applied force when the shear strength reaches 100kN/m2.

The measured values are graphically presented in real-time and plotted against the rotational angle. Simultaneously the measured values, sample number and time are logged in a separate spread sheet.

Upon completion of the undrained shear test, a remould test can be completed. The PLC will turn the vane 5 revolutions at a speed of 15° per second. To prevent damage the maximum torsion during remould is limited to 50%. After the 5 revolutions the system returns to the preset turning speed and will log the residual shear strength. If the initial 5 revolutions are insufficient, the operator can repeat the remould operation. The results of both undrained and residual shear strength are presented in the same graph.