Vibroflotation group vibration equipment and construction process

Abstract

The invention relates to vibroflotation group vibration equipment and a construction process, and belongs to the field of vibroflotation. The vibroflotation group vibration equipment comprises a plurality of vibroflotation devices, a hanging bracket and a sling, the upper ends of all the vibroflotation devices are connected with the hanging bracket, and the sling is connected with the hanging bracket. A special hanging bracket is manufactured through a pile spacing layout diagram, special vibroflotation equipment is selected, the diameter of a vibroflotation device is small and is basically the same as that of a guide rod, and the lifting resistance is small. Excitation forces of a plurality of vibroflots are accumulated to vibrate together, and the treatment area is 2-3 times of the foundation collapse degree treated by a single group. The variable-frequency hydraulic / electric vibroflots are adopted, and the frequencies of the vibroflots can be different, so that pore forming is facilitated, and the lifting resistance is reduced. The construction efficiency is high. The number of auxiliary machines is reduced, personnel cost is reduced, and safety risks are reduced. Construction with filler and construction without filler can be carried out, and the application range is wide.

Description

Technical Field

[0001] The invention relates to the field of vibro-impact technology, in particular to vibro-impact group vibration equipment and a construction process. Background Art

[0002] With the expansion of the scale of land reclamation projects, the application and development of group vibration compaction technology has been promoted. Under the same boundary conditions, since group vibration compaction can be carried out multiple times at a time, the construction efficiency can be greatly improved.

[0003] However, due to the limitation that a large number of vibrators can be used at a time, a vibrator group is often used in construction of conventional geology; for complex geology, the construction difficulty increases exponentially; for example, once a large number of vibrators collapse and get stuck in the complex geology, it is generally difficult to pull out all the vibrators at once, and each vibrator must be pulled out individually.

[0004] Based on this, the present invention is proposed. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides vibro-group vibration equipment and a construction process, and the technical solutions are as follows:

[0006] The vibratory group vibration equipment comprises a plurality of vibrators, a hanger and a sling, the upper ends of all the vibrators are connected to the hanger, and the sling is connected to the hanger.

[0007] As a further solution of the present invention, the number of the vibrators is 2i, i is a positive integer; and all the vibrators are arranged in an array.

[0008] As a further solution of the present invention, all vibrators are arranged in 2 rows, with i vibrators in each row.

[0009] As a further solution of the present invention, the vibrator is a variable frequency vibrator with a vibration frequency of 10 to 60 Hz.

[0010] As a further solution of the present invention, the number of the vibrators is 3j, where j is a positive integer; and all the vibrators are arranged in an equilateral triangle array.

[0011] As a further solution of the present invention, when i≥4, at the same time, the vibration frequencies of each row of vibrators are f1…f i-1 、f i , f1…f i-1 The Fibonacci sequence, f i-1 =2f i .

[0012] As a further solution of the present invention, at the same time, the difference in vibration frequency between two adjacent vibrators is 10-15 Hz.

[0013] As a further solution of the present invention, the distances between any two adjacent vibrators are equal.

[0014] As a further solution of the present invention, an anti-twist bar is installed on the top of the vibrator.

[0015] On the other hand, the vibro-group vibration construction process, using the vibro-group vibration equipment, comprises the following steps:

[0016] Step 1: 2-3 hours before vibroflotation construction, water the construction area;

[0017] Step 2: Align all vibrators with the vibrating holes;

[0018] Step 3: All vibrators simultaneously perform vibratory construction to form piles;

[0019] 3.1. The vibrator sinks to the bottom of the pile and remains vibrating for 60±10s;

[0020] 3.2. Pull the vibrator up to the hole mouth and keep vibrating for 120±10s;

[0021] 3.3. The vibrator sinks to 0.5±0.1m above the pile bottom and leaves it vibrating for 30±5s;

[0022] 3.4. Pull up the vibrator by 0.5±0.1m and leave it vibrating for 20±5s;

[0023] 3.5. Repeat step 3.4 until the hole is reached, and then keep vibrating for another 60±10s;

[0024] 3.6. The vibrator sinks again to 1.0±0.1m above the pile bottom and leaves vibration for 20±5s;

[0025] 3.7. Pull up the vibrator to 0.5±0.1m and leave it vibrating for 10±5s;

[0026] 3.8. Repeat step 3.7 until the orifice;

[0027] 3.9. This group of piles is finished and moves to the next group of piles.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. Make special hangers according to the pile spacing layout diagram.

[0030] 2. Use special vibratory impact equipment. The diameter of the vibrator is small, basically the same as the guide rod, and the lifting resistance is small.

[0031] 3. The exciting forces of multiple vibrators are accumulated and vibrated together, and the treated area is 2-3 times the foundation collapse degree after treatment by a single group.

[0032] 4. Use variable frequency (hydraulic or electric) vibrators. The frequencies of each group of vibrators can be different, which is convenient for hole making and reduces lifting resistance.

[0033] 5. High construction efficiency.

[0034] 6. Reduce the number of auxiliary machinery (cranes), reduce personnel costs, and reduce safety risks.

[0035] 7. Construction with or without fillers can be carried out, and the application range is wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of the vibro-group vibration equipment;

[0037] Figure 2 Schematic diagram of pile position distribution in vibroflotation construction in Example 2;

[0038] Figure 3 Schematic diagram of pile position distribution in vibroflotation construction in Example 3. DETAILED DESCRIPTION

[0039] The present invention is described in detail below in conjunction with specific embodiments. The embodiments described below are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0040] Example 1

[0041] like Figure 1 As shown, the vibro-group vibration equipment includes a plurality of vibrators 10 , a hanger 20 , and a sling 30 . The upper ends of all the vibrators 10 are connected to the hanger 20 , and the sling 30 is connected to the hanger 20 .

[0042] In this way, multiple vibrators 10 can be hoisted at one time, and multiple vibrators 10 can perform vibratory construction at the same time, which significantly improves the vibratory efficiency.

[0043] The vibrator 10 may be a fixed frequency vibrator; or a variable frequency vibrator, with a vibration frequency of 10-60 Hz; the vibrator 10 may be a variable frequency hydraulic vibrator or a variable frequency electric vibrator.

[0044] An anti-twist bar 11 is installed on the top of the vibrator 10 .

[0045] The vibro-group vibration equipment and its construction process have the following advantages:

[0046] 1. Make a special hanger 20 according to the pile spacing layout diagram.

[0047] 2. Use a special vibratory impact device (vibrator 10). The diameter of the vibrator is small, basically the same as the guide rod, and the lifting resistance is small.

[0048] 3. The exciting forces of multiple vibrators are accumulated and vibrated together, and the treated area is 2-3 times the foundation collapse degree after treatment by a single group.

[0049] 4. Use variable frequency (hydraulic or electric) vibrators. The frequencies of each group of vibrators can be different, which is convenient for hole making and reduces lifting resistance. The speed of the eccentric shaft in the variable frequency hydraulic vibrator can reach 3000r / min.

[0050] 5. High construction efficiency.

[0051] 6. Reduce the number of auxiliary machinery (cranes), reduce personnel costs, and reduce safety risks.

[0052] 7. Construction with or without fillers can be carried out, and the application range is wide.

[0053] For example, six vibrating impactors 10 are provided, and the vibrating impact group equipment is referred to as a six-head group vibrating impactor. The treatment area reaches 96 square meters at a time, the foundation treatment effect is significant, and the construction period is greatly shortened.

[0054] Example 2

[0055] In Example 1, the number of the vibrators 10 is 2i, where i is a positive integer; all the vibrators 10 are arranged in an array, such as a rectangular array, and the pile position distribution is shown in Figure 2 That is, all the vibrators 10 are arranged in 2 rows, with i vibrators 10 in each row.

[0056] During the vibro-group construction process, construction can be carried out without fillers or with fillers. However, for construction with fillers (gravel needs to be filled after the hole is made during the vibro-group construction process), if the vibro-compactors are arranged in a rectangular array of more than 2 rows (such as a 3-row rectangular array), the middle row of pile holes will have inconsistent filler amounts, which may lead to defects such as broken piles and voids. However, if the vibro-compactors are distributed in a 2-row rectangular array, even if there is filler, the filler amounts at all pile holes can be consistent, effectively avoiding defects such as broken piles and voids.

[0057] In the past, after the construction of vibro compaction without filler, the surface layer of the foundation with a thickness of about 1.0-1.5m often had a small constraint force and looseness, and the compaction effect was not good. However, the present invention adopts vibro-compaction group vibration equipment for construction, which well solves the problem of looseness and lack of compaction in the upper part.

[0058] Example 3

[0059] In Example 1, the number of the vibrators 10 is 3j, where j is a positive integer; all the vibrators 10 are arranged in an equilateral triangle array.

[0060] For construction with filler, if the vibrators are arranged in 3 rows, they cannot be arranged in a rectangular array, but must be arranged in an equilateral triangle array, such as Figure 3 As shown, according to this construction method, even if there is filler construction, the amount of filler in all pile holes can be consistent, thereby effectively avoiding defects such as broken piles and voids.

[0061] For group vibration and compaction construction, the pile layout should be in an equilateral triangle to maximize the superposition and compaction resonance effect of multiple points on the foundation soil. The reinforcement effect of multiple points and group vibration is more uniform, achieving the best foundation treatment effect. The bearing capacity of the foundation soil is greatly improved.

[0062] Example 4

[0063] For Example 2, when i≥4, at the same time (or any time), the vibration frequencies of each row of vibrators are f1…f i-1 、f i , f1…f i-1 The Fibonacci sequence, f i-1 =2f i .

[0064] For example, i=5, at a certain moment, f1=10Hz, f2=20Hz, f3=30Hz, f4=50Hz, f5=25Hz.

[0065] Specific frequency control method: The inverters of all vibrators are connected to a synchronous controller. By adjusting the output frequency and phase of the inverter, the motor speeds corresponding to the two inverters are kept in a specific ratio, so that the vibration frequencies of different vibrators are running in a specific ratio at any time.

[0066] In addition, it is also necessary to ensure that the distance between two adjacent piles is equal. For example, the distance between two adjacent piles in each row of vibrators is x, x = 2m; the distance between two adjacent piles in each column of vibrators is y, y = 2m.

[0067] Vibration construction is generally not used in hard strata because it is difficult to make holes. For example, the N value (penetration rate) of a hard soil layer 7-12m underground is 40-45kg / cm 2 When using a single vibrator, it is estimated that it will take 2-3 hours to penetrate. If the hole is made for too long, it is very easy to cause the hole to collapse or shrink.

[0068] By adopting the construction method of this embodiment, the penetration time for penetrating the hard soil layer (3 to 3.5 m) is 12 minutes. This is because in the array where the vibrators are arranged, by controlling the vibration frequency, the vibrators and the soil around them form different degrees of vibration, or even resonance, which can significantly increase the hole-making speed in the hole-making stage; in the subsequent compaction stage, the bearing capacity and shear strength of the vibratory pile can also be significantly improved (reaching more than 20 kPa).

[0069] With respect to this embodiment, if f1 = 10 Hz, f2 = 20 Hz, f3 = 30 Hz, f4 = 50 Hz, f5 = 60 Hz, the penetration time is 14 min, and the shear strength of the vibratory pile is 13-15 kPa. However, if the penetration is less than 40 kg / cm 2 In the strata, the shear strength of all vibratory piles is greater than 17kPa.

[0070] With respect to this embodiment, if f1 = 10 Hz, f2 = 20 Hz, f3 = 30 Hz, f4 = 50 Hz, f5 = 10 Hz, and the penetration time is 33 min, the shear strength of the vibratory pile is greater than 20 kPa. However, if the penetration is less than 40 kg / cm 2 In strata, the shear strength of all vibratory piles is greater than 15kPa.

[0071] With respect to this embodiment, if f1 = 10 Hz, f2 = 20 Hz, f3 = 30 Hz, f4 = 40 Hz, f5 = 50 Hz, and the penetration time exceeds 60 min, the shear strength of the vibratory pile is 10-11 kPa. However, if the penetration is less than 40 kg / cm 2 In strata, the shear strength of all vibratory piles is greater than 20kPa.

[0072] With respect to this embodiment, if f1 = 35 Hz, f2 = 35 Hz, f3 = 35 Hz, f4 = 35 Hz, f5 = 35 Hz, and the penetration time exceeds 60 min, the shear strength of the vibratory pile is 10-11 kPa. However, if the penetration is less than 40 kg / cm 2 In strata, the shear strength of all vibratory piles is greater than 20kPa.

[0073] Example 5

[0074] For Example 3, at the same time (or any time), the difference in vibration frequency between two adjacent vibrators is 10-15 Hz.

[0075] The distance between two adjacent piles is equal, and its value is z. For example, z is 2m.

[0076] The existing vibrator has a poor effect on the vibratory impact method for silty clay mixed with silty silt layers; for example, the construction method of Example 4 cannot be used for construction on silty clay mixed with silty silt layers.

[0077] In contrast, with respect to the present embodiment, at the same time, the vibration frequencies of two adjacent vibrators are equal. Due to the high looseness of the surface soil or long-term scouring, pile hole collapse is prone to occur during the construction process.

[0078] In contrast, relative to the present embodiment, at the same time, the difference in vibration frequency between two adjacent vibrators is less than 8 Hz. When the construction stratum is relatively soft, the current density may not reach the ideal current, and vibratory construction cannot be carried out in this case.

[0079] In contrast, with respect to the present embodiment, at the same time, the difference in vibration frequency between two adjacent vibrators is greater than 20 Hz, which may easily cause pile stringing during construction and cause loose collapse between piles.

[0080] By adopting the vibro-floating construction method of the present embodiment, each time a pile is formed, the pile forming area is a triangular densified area that is densified and compacted. It is possible to carry out vibro-floating construction in silty clay mixed with silty silt layers, and there will be no phenomena such as pile hole collapse, current densification failing to reach the ideal medium current, and pile stringing.

[0081] Example 6

[0082] When a 30kw conventional vibrator is used for single-hole vibratory construction, the relative density of the loose sand 0.9 meters away from the pile position after treatment will not exceed 30%; however, if the group vibration vibratory construction of Example 2 is used, the compaction effect can be superimposed within 2.5 meters, and the test results also prove this point. In the group vibration compaction test, the relative density of the loose sand after treatment is generally above 70%, and most of them are above 80%. Similarly, with the increase of the power of the vibrator, the arrangement and adjustment of the pile spacing are more flexible. Under the same treatment boundary conditions, while taking into account efficiency and cost, the relative density of the loose sand after treatment can reach 85%-90%.

[0083] Table 1 Standard penetration number of fine sand layer after treatment with 30kW vibrator

[0084]

[0085] It can be seen from Table 1 that in single-hole (unit) vibratory impact, before and after vibratory impact, as the pile spacing increases, the number of standard penetration blows decreases. When the pile spacing of a single hole is 2m, the number of standard penetration blows after vibratory impact is 1.5 times that before vibratory impact; under the same conditions, when three vibrators are used, the pile spacing is 2m, and the number of standard penetration blows after vibratory impact is 4.5 times that before vibratory impact.

[0086] The construction using the vibro-compaction group vibration equipment of the present invention has a great advantage in improving the bearing capacity of foundation soil compared with single-hole vibro-compaction.

[0087] Table 2 Standard penetration number of fine sand layer after treatment with 75KW vibrator

[0088]

[0089] It can be seen from Table 2 that for a 75kw single-hole (unit) vibratory impact, before and after vibratory impact, as the pile spacing increases, the number of standard penetration hits decreases. When the pile spacing of a single hole is 2.5m, the number of standard penetration hits after vibratory impact is 1.76 times that before vibratory impact. Under the same conditions, when three vibrators are used, the pile spacing is 2.5m, and the number of standard penetration hits after vibratory impact is 3.4 times that before vibratory impact.

[0090] The construction using the vibro-compaction group vibration equipment of the present invention has a great advantage in improving the bearing capacity of foundation soil compared with single-hole vibro-compaction.

[0091] The vibrator is a moving point vibration source in the soil, so the dilatancy zone, flow zone, compaction zone and transition zone are not fixed. As the vibrator moves, the dilatancy zone and flow zone can become compaction zone and elastic zone. The vibrating group vibration equipment of the present invention can expand the compaction zone, encrypt the transition zone, superimpose the flow zone, increase the processing area, and improve the construction efficiency. At the same time, the compaction effect is more significant.

[0092] Example 7

[0093] Foundation treatment solution:

[0094] Reinforcement target: Area 1 (foundation treatment depth is 6.5m, pile spacing is 2m);

[0095] Area 2 (foundation treatment depth is 5.5m, pile spacing is 2m);

[0096] Resistant to earthquake liquefaction. Meet the requirements of seismic fortification intensity 8 (0.185g);

[0097] The characteristic value of foundation bearing capacity fak>150kpa;

[0098] The settlement after construction is required to be no more than 40cm.

[0099] ①. Watering: Water the construction area 2-3 hours before vibroflotation to make the surface layer contain water and improve the vibroflotation effect of the upper sand and soil.

[0100] ②. Align the vibrating holes, with an error of no more than 100mm.

[0101] ③. Vibratory construction to form piles.

[0102] 3.1. Slowly vibrate and sink to the bottom of the pile, and keep vibrating for 60 seconds;

[0103] 3.2. Slowly vibrate and pull up to the hole mouth, and keep vibrating for 120 seconds;

[0104] 3.3. Slowly vibrate and sink to 0.5m above the pile bottom, and keep vibrating for 30s;

[0105] 3.4. Slowly vibrate upwards for 0.5m and leave vibration for 20s;

[0106] 3.5. Repeat step 3.4, pull up 0.5m each section, and keep vibrating for 20s each section until the hole mouth, and keep vibrating for another 60s;

[0107] 3.6. Vibrate and sink again to 1.0m above the pile bottom and leave vibration for 20s;

[0108] 3.7. Slowly vibrate upwards to 0.5m and leave vibration for 10s;

[0109] 3.8. Repeat step 3.7 until the hole mouth, pull up 0.5m each section, and keep vibration for 10s each section (if conditions permit, fill the hole with sand and compact it during the third pull-up process);

[0110] 3.9. This group of piles is finished and moves to the next group of piles.

[0111] In this example, slow vibration means that the vibrator descends at a speed of 0.5-1 m / min.

[0112] In the above-mentioned embodiment, it has been proved through many engineering practices that multi-head group vibration compaction (i.e., the use of multiple vibrators distributed in an array in the present invention) can significantly improve the settlement of the original pile sand and soil compared with a single-head (or two vibrators, three vibrators), and the effect is particularly obvious in eliminating liquefaction and improving the bearing capacity of foundation soil.

[0113] In addition, it should be understood that those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. Vibro-group vibration equipment, characterized by: The utility model comprises a plurality of vibrators, a hanger and a sling, the upper ends of all the vibrators are connected with the hanger, and the sling is connected with the hanger.

2. The vibro-group vibration equipment according to claim 1, characterized in that: The number of the vibrators is 2i, where i is a positive integer; all the vibrators are arranged in an array.

3. The vibro-group vibration equipment according to claim 2, characterized in that: All vibrators are arranged in 2 rows, with i vibrators in each row.

4. The vibro-group vibration equipment according to claim 3, characterized in that: The vibrator is a variable frequency vibrator with a vibration frequency of 10 to 60 Hz.

5. The vibro-group vibration equipment according to claim 1, characterized in that: The number of the vibrators is 3j, where j is a positive integer; all the vibrators are arranged in an equilateral triangle array.

6. The vibro-group vibration equipment according to claim 4, characterized in that: When i ≥ 4, at the same time, the vibration frequency of each row of vibrators is f1…f i-1 、f i , f1…f i-1 The Fibonacci sequence, f i-1 =2f i .

7. The vibro-group vibration equipment according to claim 5, characterized in that: At the same time, the difference in vibration frequency between two adjacent vibrators is 10 to 15 Hz.

8. The vibro-group vibration equipment according to claim 1, characterized in that: The distance between any two adjacent vibrators is equal.

9. The vibro-group vibration equipment according to claim 1, characterized in that: An anti-twist bar is installed on the top of the vibrator.

10. Vibroflotation group vibration construction technology, characterized by: The vibro-group vibration equipment according to any one of claims 1 to 9 comprises the following steps: Step 1: 2-3 hours before vibroflotation construction, water the construction area; Step 2: Align all vibrators with the vibrating holes; Step 3: All vibrators simultaneously perform vibratory construction to form piles; 3.

1. The vibrator sinks to the bottom of the pile and remains vibrating for 60±10s; 3.

2. Pull the vibrator up to the hole mouth and keep vibrating for 120±10s; 3.

3. The vibrator sinks to 0.5±0.1m above the pile bottom and leaves it vibrating for 30±5s; 3.

4. Pull up the vibrator by 0.5±0.1m and leave it vibrating for 20±5s; 3.

5. Repeat step 3.4 until the hole is reached, and then keep vibrating for another 60±10s; 3.

6. The vibrator sinks again to 1.0±0.1m above the pile bottom and leaves vibration for 20±5s; 3.

7. Pull up the vibrator to 0.5±0.1m and leave it vibrating for 10±5s; 3.

8. Repeat step 3.7 until the orifice; 3.

9. This group of piles is finished and moves to the next group of piles.

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