CN203475404U - Standard penetration test device for dividing rock weathering degree - Google Patents

Abstract

The utility model belongs to the technical field of in-situ test equipment, and relates to a standard penetration test device for dividing rock weathering degree. A guide rod is embedded in the middle of a piercer; Pad; the bottom of the hammer pad is fastened with a screw to form a probe rod; the probe rod is provided with a scale line; the penetrator with a hollow metal tube structure with a cutting edge and the probe rod are connected and fastened by a thread; There is a water outlet hole on the top of the penetrator; it is simple in structure, easy to operate, easy to install and measure, and can directly divide the degree of weathering of weathered rocks, divide strongly weathered rocks from moderately weathered rocks, and divide strongly weathered rocks into upper, middle, and lower. Subdivision of subzones.

Description

A standard penetration test device for classifying the degree of rock weathering

Technical field:

The utility model belongs to the technical field of in-situ test equipment, and relates to a standard penetration test device for classifying the degree of weathering of rocks, which is used for judging the degree of weathering of rocks in weathered rock areas and classifying types, making up for that the existing equipment can only be applied to sandy soil , cohesive soil and residual soil of weathered rock, the degree of weathering of weathered rock can be directly divided, and the upper, middle, and lower subzones of strongly weathered rock can be subdivided for relatively hard rock in strong to moderate weathering.

Background technique:

At present, the classification of rock weathering degree mostly adopts the qualitative evaluation method of engineering geology, which is comprehensively analyzed and determined from the aspects of rock structure, color, mineral composition, joint development degree and excavation difficulty, and the weathering degree is classified based on these qualitative uncertain judgments With a lot of randomness, especially when there is a gradual relationship between the two weathering grades, it is very difficult to delineate the boundary line in the transition zone. Moreover, the national standard "Code for Geotechnical Engineering Investigation" (GB50021-2001) stipulates that , for granite rocks, standard penetration tests can be used to classify the degree of weathering, N≥50 is strongly weathered; 50>N≥30 is fully weathered; N<30 is residual soil, where N is the impact However, for the classification of strongly weathered to moderately weathered rocks, the standard penetration test is not given, and the existing standard penetration equipment (standard penetrators) cannot adapt to this type of relatively hard weathered rock. Therefore, an improved standard penetration test device is designed to judge the degree of rock weathering through test indicators on site, especially for strongly weathered to moderately weathered rocks (strongly weathered is divided into upper, middle and lower sub-zones), and the weathered layer can be accurately divided. It is of great significance for excavating the bearing capacity, correctly selecting the foundation type, reducing investment and shortening the construction period.

Invention content:

The purpose of the invention of the utility model is to overcome the disadvantages of the prior art, and seek to design and provide a standard penetration test device for classifying the degree of weathering of rocks. Hammering number (N) can visually judge the degree of rock weathering.

In order to achieve the above purpose, the main structure of the utility model includes a guide rod, a piercer, a hammer pad, a probe rod, a water outlet hole and a penetrator; the guide rod is embedded in the middle of the piercer for controlling the piercer. The direction of free fall; the bottom of the piercing hammer with automatic decoupling device is provided with a hammer pad, and the piercing hammer can fall freely onto the hammer pad. The weight of the piercing hammer is 63.5kg, and the drop distance is 76cm; the bottom of the hammer pad is made of The buckle fastening connection is made of a penetrating rod; the penetrating rod is provided with a scale line for visually observing the penetration depth, and the diameter of the penetrating rod is 42mm; The rod is connected and fastened by a screw, and the penetrator is made of ultra-high-strength alloy steel. The length of the penetrator is 300mm, the inner diameter is 35mm, the outer diameter is 55mm, and the cutting edge angle is 22°; the top of the penetrator is set There are outlet holes with a diameter of 15mm.

The specific steps for the utility model to complete the standard penetration test are:

(1) Use conventional drilling tools to drill the test weathered rock layer to 5cm above the test weathered rock layer level, remove the residual soil, and protect the wall as required;

(2) Before penetration, connect the standard penetration test device, check the joint of the probe rod to ensure that the joint of the probe rod is not loose, then put the penetrator into the borehole to the bottom of the hole, and measure the borehole Depth, keep the penetrating rod vertical;

(3) When penetrating, use a piercing hammer with an automatic decoupling device for hammering to ensure a drop distance of 76cm. When the piercing hammer falls freely, reduce the frictional resistance between the guide rod and the piercing hammer to avoid piercing Eccentric and sideways sway when the mandrel hammers, and keep the guide rod, penetrating rod and penetrator vertical after being connected;

(4) Drive the penetrator into the test weathered rock formation at a penetration speed of 15-30 blows per minute, first penetrate 5cm into the test weathered rock formation according to the scale line on the penetrating rod, and the 5cm penetrated will not count the number of blows , then the number of hammer blows driven into the test weathered rock formation at 10cm is the measured hammer number N; when the penetration depth is less than 10cm, it is converted into the hammer number N with a penetration depth of 10cm according to the formula N=30n/ΔS, where n is The hammering number of any selected penetration amount, the unit is hit; ΔS is the penetration amount corresponding to the hammering number n blows, the unit is cm;

(5) Propose the penetrator, and obtain the weathering degree classification standard of the test weathered rock formation: when N<18, it is fully weathered; 30>N≥18, it is a strongly weathered upper subzone; 45>N≥30, it is a strongly weathered middle subzone ; 70>N≥45 is strongly weathered lower subzone; N≥70 is moderately weathered rock;

(6) If it is necessary to continue the penetration test at the next depth, repeat the above operation steps for the test.

Compared with the prior art, the utility model has the advantages of simple structure, convenient operation, convenient installation and reading, can directly divide the degree of weathering of weathered rocks, divide strong weathered rocks and moderately weathered rocks, and divide strong weathered rocks into upper, middle and lower parts. subdivision of subzones.

Description of drawings:

Fig. 1 is the principle schematic diagram of the main structure of the utility model.

Fig. 2 is a schematic diagram of the structure and principle of the penetrator involved in the present invention.

Fig. 3 is a schematic diagram of the cross-sectional structure of the penetrator involved in the present invention.

Detailed ways:

Below in conjunction with accompanying drawing and through embodiment the utility model is further described.

Example:

The main structure of this embodiment includes a guide rod 1, a piercing hammer 2, a hammer pad 3, a probe rod 4, a water outlet 5, and a penetrator 6; the guide rod 1 is embedded in the middle of the piercing hammer 2 for controlling The free fall direction of the piercing hammer 2; the bottom of the piercing hammer 2 with an automatic decoupling device is provided with a hammer pad 3, the piercing hammer 2 can freely fall on the hammer pad 3, and the weight of the piercing hammer 2 is 63.5kg. The drop distance is 76cm; the bottom of the hammer pad 3 is fastened with a screw to form a probe rod 4; the probe rod 4 is provided with a scale line for visually observing the penetration depth, and the diameter of the probe rod 4 is 42mm; The penetrator 6 with the hollow metal tube structure at the cutting edge and the probe rod 4 are connected and fastened by screws. The penetrator 6 is made of ultra-high-strength alloy steel. The penetrator 6 has a length of 300mm and an inner diameter of 35mm. The outer diameter is 55 mm, and the cutting edge angle is 22°; the top of the penetrator 6 is provided with a water outlet hole 5 with a diameter of 15 mm.

The specific steps for completing the standard penetration test in this embodiment are:

(1) Use conventional drilling tools to drill the test weathered rock layer to 5cm above the test weathered rock layer level, remove the residual soil, and protect the wall as required;

(2) Before penetration, connect the standard penetration test device, check the joint of the probe rod 4 to ensure that the joint of the probe rod 4 is not loose, then put the penetrator 6 into the borehole to the bottom of the hole, and measure Obtain the drilling depth and keep the probe rod 4 vertical;

(3) When penetrating, use the piercing hammer 2 with an automatic decoupling device for hammering to ensure a drop distance of 76cm. When the piercing hammer 2 falls freely, reduce the friction between the guide rod 1 and the piercing hammer 2 resistance, to avoid eccentricity and sideways shaking when the piercer 2 hammers, and keep the guide rod 1, the penetrating rod 4 and the penetrator 6 connected vertically;

(4) Drive the penetrator 6 into the test weathered rock formation at a penetration speed of 15-30 strokes per minute, first penetrate 5cm into the test weathered rock formation according to the scale line on the penetrating rod 4, and the 5cm penetrated will not be counted. The number of blows, and then the number of hammer blows driven into the test weathered rock formation of 10cm is the measured number of hammer blows N; when the penetration depth is less than 10cm, it is converted into the number of hammer blows N with a penetration depth of 10cm according to the formula N=30n/ΔS, where n is the hammering number of any selected penetration amount, the unit is stroke; ΔS is the penetration amount corresponding to the hammering number n strokes, the unit is cm;

(5) The penetrator 6 is proposed, and the weathering degree classification standard of the test weathered rock formation is obtained: when N<18, it is fully weathered; 30>N≥18 is strongly weathered upper subzone; 45>N≥30 is strongly weathered Central Asia zone; 70>N≥45 is strongly weathered lower subzone; N≥70 is moderately weathered rock;

(6) If it is necessary to continue the penetration test at the next depth, repeat the above operation steps for the test.

Claims (1)

1. A standard penetration test device for dividing the degree of rock weathering, characterized in that the main structure includes a guide rod, a piercer, a hammer pad, a penetrating rod, a water outlet hole and a penetrator; the guide rod is embedded in the piercer In the middle of the hammer; the bottom of the piercing hammer with automatic decoupling device is provided with a hammer pad, and the piercing hammer falls freely onto the hammer pad. The weight of the piercing hammer is 63.5kg, and the drop distance is 76cm; the bottom of the hammer pad is fastened with a threaded buckle The connection system is equipped with a probe rod; the scale line is set on the probe rod, and the diameter of the probe rod is 42mm; the penetrator and the penetrator of the hollow metal tube structure with a cutting edge are connected and fastened by a threaded buckle, and the penetrator The length of the penetrator is 300mm, the inner diameter is 35mm, the outer diameter is 55mm, and the cutting edge angle is 22°; the top of the penetrator is provided with a water outlet hole with a diameter of 15mm.

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