How to do deflection experiment, deflection detection method

Deflection detection methodBeckman beam method: static test, the test method is mature, and it is currently the standard method specified in the specification.

Automatic deflectometer method: It belongs to the category of static test, but the total deflection is measured.

Drop weight deflectometer method: it belongs to dynamic deflection.

Detection principle:Deflection value detection is the load on the roadbed, before and after the pavement action, the size of the deformation of the subgrade, the pavement occurs, the deflection value is calculated with 1 100 mm as the calculation unit is indicated, in a certain road section, according to the spacing of 20 meters, the vehicle with a certain axle load (generally with the rear axle 6 tons or 10 tons of vehicle) before and after the action on the roadbed pavement, the weighted average value of the residual deformation that is generated.

The deflection test is an experimental method to test the mechanical properties of an object. Its most common purpose is to evaluate the quality and strength of a material or structure to determine whether it can withstand loads and operate safely and reliably over its life expectancy. This experimental method measures the strength and stability of an object by applying a load and measuring its deformation and/or failure.

A further extension and extension of the deflection test is the analysis of the test results to determine the strength, stiffness, bending, and load-bearing capacity of the material. This testing method can help designers and engineers choose the right materials and construction methods when constructing important structures such as bridges, buildings, aircraft, ships, and vehicles. In addition, flexure tests can be used to determine material properties such as the elastic limit, fatigue life of the material, and stress-strain curves for more accurate physical models and computer simulations.

In industrial production, flexure tests are widely used to test the properties of metallic and non-metallic materials, rubber, composite materials, etc. For example, materials scientists perform such experiments to determine the stress levels that materials tolerate and how they respond to various test conditions. The operator fixes the test material at one end, applies a load, and then measures the deflection and strain of the material.

In addition, flexure testing can also be used in the medical profession to assess bone and joint health, pathological changes, or the effectiveness of plexus lead therapy, which can help determine the progress of fracture repair and determine the difference before and after surgery. While this application is not as common as materials testing, it demonstrates that flexure testing is a versatile test method that makes permeation easy to use in a wide range of ways. <>

First of all, we need to know that the deflection test is based on the control detection of subgrade construction such as highways, bridges and tunnels, and through the comparative test and correlation analysis of drop weight deflection instrument (FWD) and Beckman beam (BB) on subgrade of different road sections and different soil qualities, the control index of FWD detection subgrade is proposed.

Its bump seepage detection method Beckman beam determination subgrade pavement rebound deflection test Purpose and scope of application This method is suitable for measuring the rebound deflection of various types of subgrade pavement, is used to evaluate its overall bearing capacity, can be used for pavement structure design.

The last standard car: the truck of double axle, rear axle on both sides of 4 wheels, its standard axle load, tire size, tire clearance and tire pressure and other main parameters should meet the requirements of Table 1.

The surveyor blows the whistle and directs the car to move slowly, and the dial indicator continues to rotate forward as the deformation of the road surface increases. After the hand rotation is stable, the final reading L2 is read again.

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Deflection detection, have you learned.

Static deflectometer: This is a widely used deflectometer in China, including the bearing plate method, lever deflectometer, pavement surface curvature meter and spine orange automatic deflectometer and other types.

The vibration equipment is used to generate a sinusoidal load, which is applied to the road surface, and a group of speed or acceleration sensors are installed on the road surface to measure the pavement deflection basin to analyze the stiffness characteristics of the pavement under the action of vibration load. A specific weight falls freely from a specific height and thus impulses a load on the road surface.

Hello, I am glad to answer for you the deflection detection method 1 in the test section of the arrangement of the measurement point, the distance according to the test needs, the measurement point should be on the road lane of the wheel track, and marked with white paint or chalk. The spacing of the measurement points along the axis of the road is 5m, which is divided into left and right staggered columns. 2. Align the rear wheel clearance of the test vehicle with the position at 3 5 cm after the measurement point.

3. Insert the deflectometer into the gap between the rear wheels of the car, consistent with the direction of the car, the beam arm shall not touch the tire, the deflectometer probe is placed on the measuring point (3 5 m in front of the center of the wheel clearance), and the dial gauge is installed on the measuring rod of the deflectometer, the dial gauge is adjusted to zero, and the deflectometer is gently knocked with a finger to check whether the dial gauge is stable back to zero. The deflectometer can be measured on one side or both sides at the same time. 4. The surveyor blows the whistle and directs the car to move forward slowly, and the 100% excitation table continues to rotate forward with the increase of road deformation.

When the hand is turned to its maximum, the initial reading is quickly taken. The car is still moving forward, and the watch hand is reversed back ** After the car drives out of the radius of influence of the deflection (more than 3m), blow the whistle or wave the red Ming pure flag to command the starvation to stop.

The final reading is taken after the hand has stabilized. The speed of the car should be about 5kmh.