X-shaped vibrating rod

Abstract

The present invention discloses an X-shaped vibrating rod, which comprises a vibrating rod body. The cross-section of the vibrating rod body is in an X-shaped structure, and the oblique included angle of the X-shaped vibrating rod body is 45°-60°. Open teeth are equally spaced on the edges of the four wing edges of the vibrating rod body. Circular holes are equally spaced on the surfaces of the four wing edges of the vibrating rod body in the length direction. This X-shaped vibrating rod has a simple design structure and is convenient to use. It can avoid the soil plugging effect generated near the rod axis when a cross-shaped vibrating rod is in use, enabling the vibration energy to be effectively transmitted to achieve the best compaction effect. The designed open teeth can reduce the actual cross-sectional area and impedance of the vibrating rod, generate a larger amplitude and are prone to resonance with the soil, which is beneficial to vibration compaction. At the same time, the design of the open teeth also reduces the stiffness and weight of the vibrating rod, making it flexible when loaded. The greater the flexibility, the larger the compaction range. The geometric design of the vibrating rod can improve the compaction effect.

Description

Technical Field

[0001] The present invention relates to the design field of vibrating rods selected for the vibration compaction treatment of collapsible loess foundations, and specifically to an X-shaped vibrating rod. Background Art

[0002] In China, loess covers more than 220 counties and cities in provinces and regions such as the northwest and north China, with an area of 630,000 square kilometers, accounting for about 6.6% of the national land area. It is characterized by wide distribution, large layer thickness, and complex genetic types. The collapsibility caused by the water sensitivity, macroporosity, and structural properties of loess makes it prone to instability and landslides, seismic subsidence, and collapsibility under the action of external loads (such as earthquakes, engineering vibrations, etc.) and water. Due to its special engineering properties, loess is difficult to meet the requirements of the overlying buildings for foundation bearing capacity and stability when used as a natural foundation, and corresponding reinforcement treatments must be carried out. Common collapsible loess foundation treatment methods include dynamic compaction method, replacement cushion method, compaction pile method, pre-soaking method, and chemical reinforcement method, etc. These methods have been popularized and applied in the engineering construction of loess areas and corresponding specification standards have been formed, but they also have their own limitations. At present, although cross-shaped vibrating rods are used in some areas to reinforce loess collapsibility, the reinforcement effect of the cross-shaped vibrating rods in the actual use process is not stable and it is difficult to meet the construction requirements. Therefore, the research and development of new economic, efficient, and environmentally friendly loess foundation treatment technologies is of great significance for the loess engineering construction in the northwest region of China. Summary of the Invention

[0003] The purpose of the present invention is to provide an X-shaped vibrating rod to solve the problem of poor reinforcement effect generated by the current cross-shaped vibrating rod during loess reinforcement as proposed in the above background art.

[0004] The technical solution of the present invention is realized as follows: An X-shaped vibrating rod includes a vibrating rod body. The cross-section of the vibrating rod body is in an X-shaped structure, and the oblique angle of the X-shaped structure vibrating rod body is 45° - 60°. The four wing edges of the vibrating rod body are equally spaced with opening teeth, and circular holes are equally spaced on the surfaces of the four wings of the vibrating rod body in the length direction. One end of the vibrating rod body is a planar structure, and the other end is provided with a spiked end. The included angle between the hypotenuse of the spiked end and the center line of the vibrating rod body is 30° - 60°.

[0005] Preferably, the included angle between the hypotenuse of the spiked end and the center line of the vibrating rod body is 30°.

[0006] Preferably, the included angle between the hypotenuse of the spiked end and the center line of the vibrating rod body is 60°.

[0007] Preferably, the opening teeth on the four wings of the vibrating rod body are concave semi-circular rulers.

[0008] Preferably, the opening teeth on the four wing edges of the vibrating rod body are square teeth.

[0009] Preferably, the opening teeth on two of the wing edges of the vibrating rod body are concave semi-circular rulers, and the opening teeth on the other two wing edges are square teeth. The concave semi-circular rulers and the square teeth are arranged alternately on the vibrating rod body.

[0010] Preferably, the oblique included angle of the X-shaped vibrating rod body is 45°.

[0011] Preferably, the oblique included angle of the X-shaped vibrating rod body is 60°.

[0012] Preferably, the thickness of the four wing edges of the vibrating rod plate body is 2 cm.

[0013] By adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0014] The X-shaped vibrating rod has a simple design structure and is convenient to use. It can avoid the soil plugging effect generated near the rod axis during the use of the cross-shaped vibrating rod, enabling the vibration energy to be effectively transmitted to achieve the best compaction effect. The designed opening teeth can reduce the actual cross-sectional area and impedance of the vibrating rod, generate a larger amplitude and are easy to resonate with the soil mass, which is beneficial to vibration compaction. At the same time, the design of the opening teeth also reduces the stiffness and weight of the vibrating rod, making it flexible when loaded. The greater the flexibility, the larger the compaction range, and the geometric design of the vibrating rod can improve the compaction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 is a three-dimensional structure diagram of the present invention;

[0017] Figure 2 is a plan structure diagram of the present invention;

[0018] Figure 3 is a cross-sectional view of the present invention;

[0019] Figure 4 is a layout diagram of the test points for comparing the reinforcement effects between the present invention and the cross-shaped vibrating rod;

[0020] Figure 5 is an evaluation diagram of the collapsibility of loess after reinforcement for comparing the reinforcement effects between the present invention and the cross-shaped vibrating rod.

[0021] Figure 6 This is a comparison chart of the standard penetration test results before and after reinforcement for comparing the reinforcement effect of the present invention with a cross-shaped vibrating rod.

[0022] Wherein: 1. The vibrating rod body; 2. The opening teeth; 3. The round holes; 4. The spiked end. Specific embodiments

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0024] Refer to Figures 1 - 3 , an X-shaped vibrating rod, including a vibrating rod body 1, the cross-section of the vibrating rod body 1 is in an X-shaped structure, the oblique angle a of the X-shaped structure vibrating rod body 1 is 45° - 60°, the edges of the four wings of the vibrating rod body 1 are equally spaced with opening teeth 2, the surfaces of the four wings of the vibrating rod body 1 are equally spaced with round holes 3 in the length direction, one end of the vibrating rod body 1 is a flat structure, and the other end is provided with a spiked end 4, the included angle b between the hypotenuse of the spiked end 4 and the center line of the vibrating rod body 1 is 30° - 60°. The purpose of such a setting is that the tip is beneficial to destroying the soil structure and reducing the sinking rod resistance.

[0025] Preferably, the opening teeth 2 on the four wings of the vibrating rod body 1 are concave semi-circular rulers.

[0026] Preferably, the opening teeth 2 on the four wings of the vibrating rod body 1 are square teeth.

[0027] Preferably, the opening teeth 2 on two wings of the vibrating rod body 1 are concave semi-circular rulers, and the opening teeth 2 on the other two wings are square teeth, and the concave semi-circular rulers and the square teeth are alternately arranged on the vibrating rod body 1.

[0028] Preferably, the thickness of the four wings of the vibrating rod plate body is 2 cm. In addition, the length of the vibrating rod is determined according to the design depth of the collapsible loess foundation treatment.

[0029] This vibrating rod is connected under the vibrating hammer and suspended on a crane or a frame. The vibrating rod vibrates vertically and inserts into the soil under the excitation of the vibrating hammer. By utilizing the vibration amplification effect during the resonance of the vibrator-rod-soil system, the soil layer vibrates synchronously with the rod, significantly increasing the formation vibration, and achieving the optimal transfer of vibration energy from the vibrator to the rod and the surrounding soil to compact the soil. When the resonance frequency is adopted during the rod sinking and pulling processes, the relative slip between the rod and the surrounding soil particles is small, resulting in a decrease in the efficiency of rod sinking and pulling. Moreover, the reaction force of the pulling rod on the compacted soil layer plays an obvious decompression role, leading to a reduction in the compaction effect. When high-frequency rod sinking is adopted, the penetration resistance of the rod is mainly affected by the resistance of the soil layer at the rod end, and the skin friction on the rod side decreases, improving the rod sinking efficiency. The entire compaction process is that the vibrating rod vibrates at a high frequency (30 Hz) and sinks to the designated depth under the action of the vertical excitation force of the variable-frequency vibrating hammer and the self-weight of the vibrating rod, then hovers (for 60 s) and vibrates at the resonance frequency (about 15 Hz) to compact the soil layer, and finally pulls out the vibrating rod at a high frequency (30 Hz), transferring energy to the surrounding soil to cause vibration compaction. Only one insertion and extraction of the vibrating rod are required to complete the single-point construction. During construction, the frequency of the vibrating hammer can be changed to adapt to the optimal working conditions.

[0030] Vibratory rod sinking is similar to vibratory pile driving. Van Impe studied the empirical relationship between the peak particle velocity of the soil layer at a distance D from the pile tip and the energy E per blow of the vibrating hammer.

[0031]

[0032] In the formula: K is the vibration amplification coefficient.

[0033] Heckman's research pointed out that the vibration amplification coefficient K increases significantly with the decrease of the pile impedance, that is, the degree of vibration energy transfer from the pile to the surrounding soil layer is controlled by the pile impedance. The empirical relationship of the pile impedance is given by Peck:

[0034] I = E y ·A / c (2)

[0035] In the formula: I is the pile impedance; Ey is the Young's modulus of the pile; A is the cross-sectional area of the pile; c is the wave velocity of the pile rod.

[0036] It can be seen from Formulas 1 and 2 that the pile shape can control the amplitude generated during the pile driving process and can be used to design the vibrating rod to increase the amplitude generated during the vibration compaction process.

[0037] Designing large-size circular holes 3 on the vibrating rod and continuous large-size open teeth 2 on the wing edges can reduce the actual cross-sectional area and impedance of the vibrating rod, generate a larger amplitude and easily resonate with the soil, thus being beneficial to vibration compaction. At the same time, the open design reduces the stiffness and weight of the vibrating rod, making it flexible when loaded. The greater the flexibility, the larger the compaction range, and the geometric design of the vibrating rod can improve the compaction effect.

[0038] The cross-shaped vibrating wing (90° orthogonal rod shape) will generate a soil plugging effect near the rod axis, which affects the effective transmission of vibration energy and cannot achieve the best compaction effect. The X-shaped vibrating rod (45° - 60° obliquely intersecting rod shape) can avoid the soil plugging effect and achieve effective energy transmission to reach the best compaction effect.

[0039] The following uses in-situ tests to study the influence of the two vibrating rod forms on the reinforcement effect:

[0040] In the test area, the X-shaped vibrating rod and the cross-shaped vibrating wing are respectively used for the comparison of the reinforcement effect. The X-shaped vibrating rod is designed as a 60° obliquely intersecting rod shape, the bottom tip angle is 60°, and the wing edge is a concave semi-circular tooth. A vibrating point spacing of 1.8 m is adopted, and the reinforcement depth is 8 m. Undisturbed soil samples are taken before and after reinforcement for the test of the collapsibility coefficient of loess. Before reinforcement, the standard penetration test (SPT) is carried out. After reinforcement, SPT is carried out at the center of 3 vibrating points arranged in a triangle at the age of 14 days. The layout of the test points is shown in Figure 4 .

[0041] From Figure 5 it can be seen that the collapsibility coefficient of loess after reinforcement with the two vibrating rods is greatly reduced compared with that before reinforcement, reaching the non-collapsible target. Among them, the collapsibility coefficient of loess in the test area of the X-shaped rod is much lower than that in the test area of the cross-shaped rod, indicating that the X-shaped vibrating rod has a better reinforcement effect than the cross-shaped vibrating wing.

[0042] The results of the standard penetration test before and after reinforcement are shown in Figure 6 as shown. The number of blows of the standard penetration test after reinforcement with the two vibrating rods has increased significantly compared with that before reinforcement. Among them, the number of blows in the test area of the cross-shaped rod has increased by 2 times, and the number of blows in the test area of the X-shaped rod has increased by more than 3 times. The number of blows and the increase amplitude of the standard penetration test in the test area of the X-shaped rod are higher than those in the test area of the cross-shaped rod, indicating that the X-shaped vibrating rod has a better reinforcement effect than the cross-shaped vibrating wing.

[0043] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An X-shaped vibrating rod, characterized in that: It includes a vibrating rod body (1). The cross-section of the vibrating rod body (1) is in an X-shaped structure. The oblique angle of the X-shaped vibrating rod body (1) is 45° - 60°. Open teeth (2) are evenly spaced on the edges of the four wings of the vibrating rod body (1). Circular holes (3) are evenly spaced on the surfaces of the four wings of the vibrating rod body (1) in the length direction. One end of the vibrating rod body (1) is a planar structure, and the other end is provided with a spiked end (4). The included angle between the hypotenuse of the spiked end (4) and the center line of the vibrating rod body (1) is 30° - 60°; The thickness of the four wings of the X-shaped vibrating rod plate body is 2 cm each; The X-shaped vibrating rod is applied to the reinforcement and compaction treatment of collapsible loess foundation by vibration; The open teeth (2) on two wings of the vibrating rod body (1) are concave semi-circular rulers, and the open teeth (2) on the other two wings are square teeth. The concave semi-circular rulers and the square teeth are alternately arranged on the vibrating rod body (1).

2. The X-shaped vibrating rod according to claim 1, wherein: The included angle between the hypotenuse of the spiked end (4) and the center line of the vibrating rod body (1) is 30°; 3. The X-shaped vibrating rod according to claim 1, wherein: The included angle between the hypotenuse of the spiked end (4) and the center line of the vibrating rod body (1) is 60°; 4. The X-shaped vibrating rod according to claim 1, wherein: The oblique angle of the X-shaped vibrating rod body (1) of the X-type structure is 45°; 5. The X-shaped vibrating rod according to claim 1, characterized in that: The oblique angle of the X-shaped vibrating rod body (1) of the X-type structure is 60°;

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