An SPT drill rig is a drilling machine used for standard penetration testing in soil investigation. It drives a split-barrel sampler into the ground using a 140 lb (63.5 kg) hammer dropped from 30 inches (760 mm) height. The test measures the number of blows needed to penetrate each 6-inch interval. This number is called the N-value. It helps engineers understand soil strength for building foundations. The machine is commonly used for construction sites, bridge projects, and road building. If you need reliable soil testing equipment, contact YG for more product information.
YG SPT Drill Rig Parameters-OEM Support
Understanding the specifications helps you choose the right equipment for your testing needs. YG offers four models to meet different project requirements:
| Model | YGX-400 | YGX-600 | YGX-800 | YGX-1000 |
| Drilling Depth(M) | 180-400-500 | 200-600-650 | 400-800-1000 | 500-1000-1100 |
| Rated pressure(MPA) | 21 | 21 | 25 | 28 |
| Rated Flow(L/min) | 168 | 192 | 260 | 300 |
| Heat Dissipation Mode | Air cooling+water cooling | |||
| Engine Brand | Yuchai | Yuchai | Yuchai | Cummins |
| Rated power/speed | 78kW/ 2400r/min | 92kW/ 2400r/min | 92kW/ 2400r/min | 154kW/2400r/min |
| Drilling Angle(°) | 0-90 | 45-90 | 45-90 | 45-90 |
| Lifting Force(T) | 12 | 16 | 24 | 30 |
| Feed Force(T) | 6 | 8 | 12 | 15 |
| Hydraulic Mud pump flow | 30-90（L/min） | 30-90（L/min） | 90-180（L/min） | 90-180（L/min） |
| Hydraulic Mud pump power | 4-7(MPA) | 4-7(MPA) | 4-7(MPA) | 4-7(MPA) |
| Dimension | 4000*1900*1800mm | 4000*2000*1800mm | 5500*2100*2000mm | 6000*2200*2400mm |
| Weight | 4.3T | 4.5/5.5T | 6.5T | 7.5T |
These numbers affect what the SPT drilling machine can achieve. Deeper drilling depth allows testing at greater depths. Higher lifting force handles heavier drill rods. The YGX-400 is good for shallow foundation projects. The YGX-1000 handles deep geotechnical surveys.
5 Steps Working Process of SPT Drill Rig
The working principle of an SPT drill rig follows a standard process. Each step is important for accurate soil testing.
Drilling the Borehole
First, the rig drills a hole to the test depth. This is done using augers or rotary wash drilling methods. The hole is cleaned out before testing starts.
Setting Up the Sampler
A split-barrel sampler is attached to the bottom of the drill rods. The sampler is lowered to the bottom of the borehole. It has a 2-inch (50 mm) diameter opening.
Performing the Hammer Test
A 140 lb (63.5 kg) hammer is lifted and dropped from 30 inches (760 mm) height. The hammer strikes the drill rods. The blows drive the sampler into the soil.
Recording the N-Value
The operator counts the blows for three 6-inch (150 mm) intervals. The first 6 inches is a seating drive. The blows for the next two 6-inch intervals are added together. This total is the SPT N-value.
Taking the Soil Sample
After the test, the sampler is pulled up. The soil inside the sampler is collected and labeled. This sample is used for laboratory testing.
SPT Drilling Machine Applications
An SPT rig is used in many geotechnical settings. Here are the most common uses:
Building Foundation Design
Engineers use SPT results to design building foundations. The N-value tells them how strong the soil is. This helps decide if a building needs piles or a shallow foundation.
Bridge Construction
Bridges need deep foundations. SPT testing shows what kind of soil is under the riverbed. This helps engineers design safe bridge supports.
Highway and Road Projects
Road builders test the soil along the route. The SPT machine helps them find soft spots. This prevents roads from sinking or cracking later.
Dams and Reservoirs
Dam construction needs careful soil testing. The SPT drilling machine checks the soil at different depths. This ensures the dam will hold water safely.
Environmental Site Investigation
SPT testing also collects soil samples. These samples are tested for contamination. This is important for industrial site cleanups.
Real-World Usage Case
Building Foundation Project
A contractor uses a YGX-400 SPT rig for a high-rise building. The rig tests soil at 30-meter depth. The N-values show strong soil at 15 meters. The foundation is designed for shallow footings. This saves money on deep piles.
Bridge Construction
A city uses a YGX-800 SPT drilling machine for a new bridge. The rig tests soil under the river to 60 meters. The N-values help design the bridge piers. The project stays on schedule with reliable equipment.
Road Project
A highway department uses a YGX-600 SPT rig for road expansion. The rig tests soil every 50 meters along the route. Soft spots are identified and treated. The road is built to last.
Common Problems and Solutions
| Problem | Possible Cause | Solution |
| Low N-value readings | Hammer drop height too low | Check and adjust drop height to 760 mm |
| Sampler not driving | Soil too dense or rocky | Switch to larger reamer or stop testing |
| Hammer rope slipping | Rope worn or too slick | Replace rope; use proper turns |
| Drill rods bending | Too much downforce | Reduce feed pressure; use straighter rods |
| Mud pump low flow | Clogged filter or worn pump | Clean filter; check pump parts |
Regular inspection prevents most issues. Keep spare parts like rope and pump parts on hand. For persistent problems, contact YG for support.
Frequently Asked Questions about SPT Drill Rig
Q1: What is the SPT N-value?
The N-value is the number of hammer blows needed to drive the sampler through the final 12 inches (300 mm) of soil. It shows soil density and strength. Higher N-values mean stronger soil.
Q2: How deep can an SPT drill rig go?
It depends on the model. YGX-400 goes 500 meters. YGX-1000 goes 1100 meters. The actual depth depends on soil conditions and rig setup.
Q3: What is a split-barrel sampler?
It is a hollow steel tube split into two halves. It collects soil samples during the test. The sampler is 2 inches (50 mm) in diameter. It is driven into the ground by the hammer.
Q4: Can this machine also do core drilling?
Yes, YG SPT rigs support both soil sampling and core drilling. They can switch between SPT testing and rotary core drilling. This makes them versatile for different projects.
