Portable motorized pressuremeter and method for calculating in situ soil properties
Portable motorized pressuremeter system, device and method calculating soil strengths and stiffnesses. The system uses a controller, external water supply and balloon probe. Controller houses a data acquisition card, electric motor with encoder, hydraulic pump, pressure transducer, rechargeable battery. A ground engaging balloon probe is placed into a soil borehole. A switch is activated and the computer drives the encoded electric motor to pump water via saturated tubing via the pump to radially inflate the balloon in up to approximately 20 equal volume increments until the balloon is approximately 50% larger than an initial filled position in the borehole. In a single operation that runs within approximately five minutes, the motor moves water through the pump to apply pressure on the borehole walls, while pressure and volume are recorded at each fluid injection increment. The computer accurately calculates soil stiffness and soil strength for the soil around the borehole.
1 . A portable motorized pressuremeter for calculating in situ soil properties, comprising;
a controller unit housing connected to a computing device, the controller unit housing an electric motor with encoder, for running a hydraulic piston pump, a pressure transducer, a data acquisition card, a rechargeable battery power supply for providing power to the electric motor and an exterior water supply;
a ground engaging balloon probe connected via tubing to the exterior water supply, the probe to be placed into a borehole in soil with tubing connected to the pressure transducer; and
a single switch for the controller unit housing, wherein activating the single switch causes the electric motor to pump water by the hydraulic piston pump from the water supply into the fully saturated hydraulic piston pump to radially inflate the long cylindrical balloon using up to approximately 20 volume increments until the balloon is approximately 50% larger than an initial filled position when the inflated balloon is first in contact with walls in the borehole, and pressure data is recorded at each volume increment, and the computer software accurately calculates soil stiffness and soil strength, from each of the increments in a single operation that runs within approximately ten minutes.
2 . The portable motorized pressuremeter of claim 1 , wherein the water supply includes:
distilled water supply.
3 . The portable motorized pressuremeter of claim 1 , wherein the single operation to determine soil strength and stiffness runs within approximately five minutes.
4 . The portable motorized pressuremeter of claim 1 , wherein the single operation to determine soil engineering properties runs within approximately three minutes.
5 . The portable motorized pressuremeter of claim 1 , wherein each increment between recordings is between approximately 15 to approximately 30 seconds.
6 . The portable motorized pressuremeter of claim 1 , wherein the water supply for the control unit is a portable plastic container jug selected from the group consisting of a ¼ gallon ½ gallon, 1 gallon, and 2 gallons, the plastic jug includes a flat bottom portion for allowing the jug to remain upright when resting on a generally level surface.
7 . The portable motorized pressuremeter of claim 6 , wherein, the water supply is one gallon of water.
8 . The portable motorized pressuremeter of claim 7 , further comprising:
anti-freeze in the water supply for allowing operation of the pressure meter below freezing conditions.
9 . The portable motorized pressuremeter of claim 6 , further comprising:
a water supply tubing having one end placed into an upper opening of the jug to below water level in the jug, and a second end attached to a water supply quick connect coupling on the controller unit housing.
10 . The portable motorized pressuremeter of claim 9 , further comprising:
a probe connection tubing having one end attached to the balloon probe, and a second end attached to another quick connect coupling on the controller unit housing; and
a valve inside the controller unit housing to switch between the water supply quick connect coupling and the another quick connect coupling in order to saturate all tubing and the hydraulic pump, or conduct tests for recording volume data and pressure data at each volume increment.
11 . The portable motorized pressuremeter of claim 10 , wherein the water supply quick connect coupling and the another quick connect coupling are formed from stainless steel.
12 . The portable motorized pressuremeter of claim 1 , wherein the hydraulic piston pump has a piston head that moves between a retracted position, and an extended position.
13 . The portable motorized pressuremeter of claim 1 , wherein the probe includes an approximately ¾ diameter.
14 . The portable motorized pressuremeter of claim 1 , wherein the control unit housing includes dimensions of up to approximately 8 inches by up to approximately 18 inches by up to approximately 24 inches, and includes an overall weight between approximately 25 to approximately 35 pounds.
15 . The portable motorized pressuremeter of claim 1 , wherein the rechargeable battery is approximately 24 volts.
16 . The portable motorized pressuremeter of claim 1 , wherein the hydraulic pump has a piston head that moves between a retracted position and an extended position to allow for a saturation process of components in the controller unit housing and to allow for recording volume and pressure data for calculating in situ soil properties.
17 . A method for calculating in-situ soil properties with a portable pressure meter onsite, comprising the steps of:
coring an approximately 1-inch hole into a soil surface to form a borehole;
providing a portable ground engaging balloon probe having a diameter of approximately ¾ if an inch, to be inserted into the borehole;
providing a portable controller unit housing an electric motor with encoder, for running a hydraulic piston pump, a pressure transducer, a data acquisition card, a rechargeable battery power supply for providing power to the electric motor and an exterior water supply
attaching a controller unit housing connected to a computing device, the controller unit housing an electric motor with encoder, for running a hydraulic piston pump, a pressure transducer, a data acquisition card, a rechargeable battery power supply for providing power to the electric motor;
providing a portable water supply of up to approximately two gallons;
connecting the ground engaging balloon probe to the exterior water supply, the probe; and
activating a switch for the controller unit, to cause the electric motor to pump water by the hydraulic piston pump from the water supply to radially inflate the long cylindrical balloon using up to approximately 20 volume increments until the balloon is approximately 50% larger than an initial filled position when the inflated balloon is first in contact with walls in the borehole, and pressure data is recorded at each volume increment, and the computer software accurately calculates soil stiffness and soil strength, from each of the increments in a single operation that runs within approximately ten minutes.
18 . The method of claim 17 , wherein the water supply for the control unit is a portable plastic container jug selected from the group consisting of a ¼ gallon ½ gallon, 1 gallon, and 2 gallons, wherein the plastic jug includes a flat bottom portion for allowing the jug to remain upright when resting on a generally level surface.
19 . The method of claim 17 , further comprising the steps of:
providing a water supply tubing having one end placed into an upper opening of the jug to below water level in the jug, and a second end attached to a water supply quick connect coupling on the controller unit housing;
providing a probe connection tubing having one end attached to the balloon probe, and a second end attached to another quick connect coupling on the controller unit housing; and
providing a valve inside the controller unit housing to switch between the water supply quick connect coupling and the another quick connect coupling in order to saturate all tubing and the hydraulic pump, or conduct tests for recording volume data and pressure data at each volume increment.
20 . The method of claim 17 , further comprising the steps of:
providing the hydraulic pump with a piston head that moves between a retracted position and an extended position to allow for a saturation process of components in the controller unit housing and to allow for recording volume and pressure data for calculating in situ soil properties.