Method for controlling the permeability of vibroflotation stone piles

Abstract

The application discloses a method for controlling water permeability of a vibro-replacement stone pile, which comprises the following steps: rapidly completing vibro-replacement construction of a stone pile hole; performing hole cleaning treatment on the stone pile hole, and obtaining mud density in the stone pile hole during the hole cleaning treatment by using a mud pump; controlling water flow and air flow according to the mud density obtained by the mud pump, so that the mud density in the stone pile hole meets the requirements; after the hole cleaning treatment is completed, the stone filling is put into the stone pile hole, and the stone filling in the stone pile hole is subjected to vibro-replacement compaction construction by using a vibrator, so as to form a vibro-replacement stone pile with an effective pile diameter. The method ensures that the water permeability in the stone pile hole meets preset requirements, so that the water permeability of an ultra-deep vibro-replacement stone pile formed under an ultra-deep overburden layer in a super-strong earthquake zone is good, and the vibro-replacement stone pile is safe and stable under strong earthquakes.

Description

Technical Field

[0001] This invention relates to the field of pile driver construction technology, and in particular to a method for controlling the permeability of vibratory stone crushing piles. Background Technology

[0002] Vibro-compaction is a method of foundation treatment that uses horizontal vibration of a vibro-compactor and the combined action of high-pressure water or high-pressure air to compact loose foundation soil layers; or, after drilling holes in the foundation soil layers, backfilling with stable, hard, coarse-grained materials, and then forming a reinforced structure (vibro-compacted pile) through vibration compaction, which together with the surrounding foundation soil forms a composite foundation.

[0003] During the vibro-compaction process, different construction methods are used for strata with different geological conditions. If a special stratum with a complex structure is encountered, and the construction effect cannot be guaranteed even with the combined action of horizontal vibration of the vibro-compaction device and high-pressure water, high-pressure air can be used as an auxiliary. The stratum is pre-damaged by the combined action of high-pressure water and high-pressure air, which helps to improve the penetration and hole-making capabilities of the vibro-compaction device.

[0004] However, the provisions regarding water supply pressure and volume in the "Technical Specification for Vibro-Compaction Foundation Treatment in Hydropower and Water Conservancy Projects" (DL / T524-2016) are merely a general summary based on engineering practice (the current construction level of vibro-compaction gravel piles in China is within 35m, and all are shallow-hole vibro-compaction with relatively simple strata). It only provides a general range for the water pump's supply pressure and volume, without specifying the appropriate water pressure for different strata or for air supply. For ultra-deep overburden layers, mostly over 100m thick, the presence of weak interlayers (such as lacustrine sedimentary silty clay) and relatively dense hard layers (such as sand layers or sand layers interbedded with gravel) presents entirely different problems during borehole drilling. This is especially true when the strata are located in areas with extremely strong earthquakes, rendering the above provisions completely inapplicable.

[0005] In addition, conventional vibro-compaction methods are not suitable for strata with thick overburden and frequent strong earthquakes, especially those prone to mega-earthquakes, because conventional vibro-compaction methods cannot ensure the permeability of the crushed stone piles and cannot guarantee that the piles will not break under the conditions of mega-earthquakes. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned problems and provide a method for controlling the permeability of vibratory compaction stone piles, ensuring that the permeability inside the stone pile hole meets the preset requirements, so as to guarantee good permeability of ultra-deep vibratory compaction stone piles formed under ultra-deep overburden in ultra-strong earthquake zones.

[0007] To achieve the above-mentioned objectives of this invention, this invention provides a method for controlling the permeability of vibratory compaction stone piles, comprising:

[0008] By controlling the water launch of the vibratory compaction stone pile machine, which includes telescopic guide rods and vibratory compactors, the vibratory compaction construction of the stone pile hole with stone filling can be completed quickly.

[0009] The holes of the crushed stone piles were cleaned, and the density of the mud in the holes during the cleaning process was obtained by a mud pump.

[0010] The flow rate of the water supplied and the flow rate of the pressurized air supplied are controlled according to the mud density obtained from the mud pump, so that the mud density in the crushed stone pile hole meets the requirements.

[0011] Continue the hole cleaning process with the required mud density until the hole cleaning process is completed;

[0012] After the hole cleaning process is completed, crushed stone filler is placed into the crushed stone pile hole, and a vibratory compactor is used to compact the crushed stone filler in the crushed stone pile hole to form a vibratory crushed stone filler pile with an effective pile diameter.

[0013] Preferably, the mud density inside the crushed stone pile hole obtained by the mud pump during the hole cleaning process includes:

[0014] The mud pump is used to pump the mud from the crushed stone pile hole upwards to the mud density meter.

[0015] The density of the pumped mud is measured using a mud density meter to obtain the current mud density value inside the crushed stone pile hole.

[0016] Preferably, the mud density meter is installed on the ground.

[0017] Preferably, the flow rate of the supplied water and the flow rate of the supplied pressurized air are controlled according to the obtained mud density to ensure that the mud density in the crushed stone pile hole meets the requirements, including:

[0018] After obtaining the current mud density value in the crushed stone pile hole, compare the current mud density value with the preset mud density threshold.

[0019] Based on the comparison between the current mud density value and the preset mud density threshold, the flow rate of the supplied water and the flow rate of the supplied pressurized air are controlled so that the mud density in the crushed stone pile hole meets the requirements.

[0020] Preferably, controlling the flow rate of the supplied sewage and the flow rate of the supplied pressurized air, based on the comparison between the current mud density value and the preset mud density threshold, includes:

[0021] The comparison result is that when the current mud density value is within the preset mud density threshold, the hole cleaning process is controlled at the current water flow rate and the current air flow rate.

[0022] The comparison result is that when the current mud density value exceeds the preset mud density threshold, the flow rate of the supplied water and the flow rate of the supplied pressurized air are controlled so that the mud density value is within the preset mud density threshold.

[0023] Preferably, when the comparison result shows that the current mud density value exceeds the preset mud density threshold, if a hole collapse occurs during the process of controlling the flow rate of the supplied water and the flow rate of the supplied pressurized air, chemical mud wall protection treatment is applied to the crushed stone pile hole.

[0024] Preferably, by controlling the water flow of the vibratory compaction pile machine, which includes a telescopic guide rod and a vibratory compactor, the vibratory compaction construction of the crushed stone pile hole is completed quickly, including:

[0025] The pipe used to supply sewage passes through the telescopic guide rod and the vibratory flusher and extends from the bottom of the vibratory flusher so that the sewage is sprayed out from the bottom of the vibratory flusher to pre-damage the formation with water.

[0026] Obtain the current formation density during vibro-compaction construction;

[0027] Obtain the instantaneous drainage pressure of the supplied water and determine the obtained instantaneous drainage pressure as the current drainage pressure;

[0028] Based on the preset correspondence between groundwater pressure and formation density, find the target groundwater pressure corresponding to the current formation density;

[0029] Control the flow rate of the supplied water to bring the current water pressure to the target water pressure, so as to complete the vibratory compaction of the crushed stone pile hole by using the vibratory compactor and the target water pressure.

[0030] Preferably, obtaining the current formation density includes:

[0031] Obtain the current oscillation current of the oscillator;

[0032] Based on the preset relationship between vibratory current and formation density, find the formation density corresponding to the current vibratory current.

[0033] The found formation density is determined as the current formation density.

[0034] Preferably, obtaining the current pulse current of the oscillator includes:

[0035] Obtain the instantaneous value of the vibration current of the vibrator;

[0036] The instantaneous value of the acquired oscillation current is determined as the current oscillation current.

[0037] Preferably, obtaining the current pulse current of the oscillator includes:

[0038] Obtain multiple instantaneous values ​​of the oscillating current of the oscillator;

[0039] The average value of the multiple instantaneous values ​​of the oscillation current is obtained by averaging the values.

[0040] The average oscillation current is determined as the current oscillation current.

[0041] Preferably, the vibratory compaction method involves using a vibratory compactor to compact and densify the crushed stone filling material within the pile hole, forming a vibratory compacted crushed stone filling pile with an effective pile diameter, including:

[0042] During the vibratory compaction of the crushed stone filling material in the crushed stone pile hole, a microphone installed inside the vibratory compactor housing is used to detect the real-time vibration signal of the vibratory compactor when it vibrates the crushed stone filling material embedded in the soil layer around the crushed stone pile hole.

[0043] Based on the real-time vibration signal of the vibratory compactor detected by the microphone located inside the vibratory compactor housing, the vibratory compactor is controlled to vibrate the gravel-filled pile, so that the diameter of the gravel-filled pile formed by the vibratory compactor vibrating and filling the gravel-filled pile hole is equal to the effective pile diameter.

[0044] Preferably, controlling the vibration of the vibratory compactor on the stone pile based on the real-time vibration signal detected by the microphone located inside the vibratory compactor housing includes:

[0045] By converting the real-time vibration signal of the oscillator detected by the pickup into the frequency domain, the main frequency of the real-time vibration signal of the oscillator is obtained.

[0046] Compare the main frequency of the real-time vibration signal of the vibratory impactor with a preset frequency;

[0047] When the main frequency of the real-time vibration signal of the vibratory compactor reaches or approaches the preset frequency, it is determined that the diameter of the crushed stone pile to be formed is equal to the effective pile diameter, and the vibratory compactor is lifted upward to vibrate and compact the crushed stone in the middle part of the crushed stone pile to be formed, thereby finally forming a crushed stone pile with a pile diameter equal to the effective pile diameter.

[0048] When the main frequency of the real-time vibration signal of the vibratory compactor is greater than the preset frequency, the vibratory compactor is controlled to continue vibrating the crushed stone embedded in the soil layer around the crushed stone pile hole.

[0049] Preferably, the preset frequency is the main frequency of the vibrator vibration signal when the vibrator amplitude is reduced to the minimum.

[0050] Preferably, controlling the vibration of the vibratory compactor on the stone pile based on the real-time vibration signal detected by the microphone located inside the vibratory compactor housing includes:

[0051] By converting the vibration signal of the front vibrator detected by the microphone in front and the vibration signal of the rear vibrator detected behind into the frequency domain, the main frequency of the vibration signal of the front vibrator and the main frequency of the vibration signal of the rear vibrator are obtained.

[0052] The dominant frequencies of the vibration signals of the preceding and following vibratory impactors were analyzed during the vibration period.

[0053] When the main frequency of the vibration signal of the rear vibratory compactor is lower than that of the main frequency of the vibration signal of the front vibratory compactor and remains so for a period of time, it is determined that the diameter of the crushed stone pile to be formed is equal to the effective pile diameter. The vibratory compactor is then raised to vibrate and compact the crushed stone in the middle part of the crushed stone pile to be formed, thus ultimately forming a crushed stone pile with a pile diameter equal to the effective pile diameter.

[0054] Preferably, the microphone disposed inside the housing of the vibrator includes a sound sensor and an audio amplifier.

[0055] Preferably, the microphone located inside the housing of the vibratory impactor is a sound sensor.

[0056] Compared with the prior art, the method for controlling the permeability of vibratory compaction stone piles of the present invention has the following beneficial effects:

[0057] 1. The present invention provides a method for controlling the permeability of vibratory compaction stone piles. This method involves real-time monitoring of the mud density during the cleaning process of the stone pile holes formed by vibratory compaction. This ensures that the permeability within the stone pile holes meets preset requirements, thus providing a prerequisite for ensuring that the permeability of the stone piles formed by subsequent vibratory compaction of the stone filler material into the stone pile holes also meets the requirements. This guarantees that even under severe earthquake conditions (such as 8.5-9 magnitude earthquakes), the excess pore water pressure from deep within the strata can still be vertically transmitted along the stone piles, preventing breakage accidents during strong earthquakes and improving the stability and safety of the composite foundation formed by the stone piles.

[0058] 2. The method of the present invention, for complex strata with deep overburden, precisely controls the supply of water pressure according to the different densities of the strata, so that the vibratory compactor and the appropriate water pressure work together to successfully complete the deep hole vibratory compaction construction in complex strata, thereby solving the problem of vibratory compaction construction in strata with deep overburden of more than 50m.

[0059] 3. The method of the present invention averages the instantaneous values ​​of the vibratory current obtained from strata with uneven local distribution, avoiding frequent adjustments to the water supply pressure due to frequent changes in the vibratory current, ensuring stable water supply from the pump and extending the service life of the pump.

[0060] 4. The method of the present invention enables the crushed stone pile to be tightly bonded to the surrounding soil layer, so that the pile diameter of the crushed stone pile truly meets the design requirements.

[0061] The present invention will now be described in detail with reference to the accompanying drawings. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of the method for controlling the permeability of vibratory compaction stone piles according to the present invention;

[0063] Figure 2 This is a schematic diagram of the vibratory stone crushing pile machine used in this invention;

[0064] Figure 3 This is a schematic block diagram of the drainage control system of the vibratory stone crushing pile machine of the present invention;

[0065] Figure 4 This is a flowchart of a method for obtaining the current formation density according to an embodiment of the present invention;

[0066] Figure 5 This is a flowchart of the drainage control method according to an embodiment of the present invention;

[0067] Figure 6 This is a schematic diagram of the present invention, in which a microphone is installed inside the housing of the vibratory impactor;

[0068] Figure 7 This is a schematic diagram of the encryption control part of the present invention, which is used to control the vibratory compactor to encrypt the crushed stone filler.

[0069] Figure 8 yes Figure 7 A flowchart of the first embodiment of the encryption control section in the system performing vibration encryption control;

[0070] Figure 9 yes Figure 7 A flowchart of the second embodiment of vibration encryption control in the encryption control section;

[0071] Figure 10 This is a flowchart illustrating the process of controlling mud density according to the present invention. Detailed Implementation

[0072] like Figure 1 The diagram shown is a flowchart of the method for controlling the permeability of vibratory compaction stone piles according to the present invention. Figure 1 It can be seen that the method of the present invention includes:

[0073] By controlling the water launch of the vibratory compaction stone pile machine, which includes telescopic guide rods and vibratory compactors, the vibratory compaction construction of the stone pile hole with stone filling can be completed quickly.

[0074] The holes of the crushed stone piles were cleaned, and the density of the mud in the holes during the cleaning process was obtained by a mud pump.

[0075] The flow rate of the water supplied and the flow rate of the pressurized air supplied are controlled according to the mud density obtained from the mud pump, so that the mud density in the crushed stone pile hole meets the requirements.

[0076] Continue the hole cleaning process with the required mud density until the hole cleaning process is completed;

[0077] After the hole cleaning process is completed, crushed stone filler is placed into the crushed stone pile hole, and a vibratory compactor is used to compact the crushed stone filler in the crushed stone pile hole to form a vibratory crushed stone filler pile with an effective pile diameter.

[0078] The invention controls the permeability of vibratory crushed stone piles during the construction process of the vibratory crushing stone pile machine. Figure 2 The diagram shows the structure of the vibratory compaction stone pile driver 1000 used in the construction process of this invention. Figure 2 As shown, the vibratory compaction stone pile machine 1000 includes a hoisting device, a guide rod 10, a vibratory compactor 13, and an automatic feeding device.

[0079] Specifically, the hoisting device includes the main unit of the vibratory stone crushing pile machine, the mast 11 connected to the main unit, and the main winch device installed at the rear of the main unit. The guide rod 10 is hoisted by the wire rope of the main winch device and the mast 11 so that the guide rod is vertically positioned under its own weight.

[0080] In addition, an automatic feeding device is installed on the main unit, which is located at the rear of the hoisting device and can be used as a counterweight for the main unit. The automatic feeding device includes a pneumatic winch, a cable winch, and a water pipe winch, and these three devices are configured to feed synchronously with the main winch.

[0081] The guide rod 10 has an upper connecting section for connecting to the wire rope of the main winch, a middle support section, and a lower working section for connecting to the vibratory compactor 13. The guide rod 10 is telescopic, allowing its axial length to be adjusted to change the lowering or raising position of the vibratory compactor system relative to the ground. Specifically, the guide rod 10 has multiple layers of sleeves sequentially connected from the inside out, with the connecting section being the top layer sleeve, the working section the bottom layer sleeve, and the support section including one or more intermediate sleeves. Adjacent layers of sleeves can be connected together using existing connection structures, ensuring smooth axial sliding between adjacent layers while preventing mutual torsion. During operation, the number and length of the multiple layers of sleeves in the guide rod can be determined according to usage requirements; for example, more than four layers of sleeves can be used, with each layer being 18-25 meters long (the top layer sleeve can be even longer). When in use, the length of the multi-layer sleeve of the guide rod can be extended or shortened. When all the multi-layer sleeves of the telescopic guide rod are extended, the total length of the telescopic guide rod can reach 100 meters or even longer. Therefore, the vibratory crushing stone pile machine of the present invention can be used to vibrate and crush holes in strata with a depth greater than 50 meters.

[0082] Vibro-compaction stone pile construction typically includes: 1) vibro-compaction to form stone pile holes, 2) cleaning the stone pile holes, 3) putting stone filler into the stone pile holes, and 4) vibro-compaction to compact the stone filler in the stone pile holes to form stone piles.

[0083] This invention forms stone pile holes by controlling the water flow of a vibratory stone crushing pile machine, including: obtaining the current ground compaction during vibratory compaction; and controlling the water flow rate supplied by the water pump in real time according to the current ground compaction, so that the vibratory compactor and the water flow work together to quickly construct the stone pile holes.

[0084] This invention automatically controls the water supply based on the current formation density, making it suitable for both shallow-hole vibratory compaction in relatively simple formations and deep-hole vibratory compaction in complex formations, ensuring the smooth progress of shallow or deep-hole vibratory compaction operations.

[0085] like Figure 5 As shown, this embodiment provides a method for controlling the drainage of a vibratory compaction stone pile driver, including:

[0086] S100, the pipe for supplying sewage passes through the telescopic guide rod and the vibratory flusher and extends from the bottom of the vibratory flusher so that the sewage is sprayed out from the bottom of the vibratory flusher to pre-damage the formation with water.

[0087] S101, obtain the current formation density during vibro-compaction construction;

[0088] S102, obtain the instantaneous drainage pressure of the supplied drainage, and determine the obtained instantaneous drainage pressure as the current drainage pressure;

[0089] S103, based on the preset correspondence between groundwater pressure and formation density, find the target groundwater pressure corresponding to the current formation density;

[0090] S104, control the flow rate of the supplied water to make the current water pressure reach the target water pressure, so as to complete the vibratory flushing construction by using the vibratory flusher and the target water pressure.

[0091] like Figure 4 As shown, the current formation density obtained during the vibro-compaction process by S101 includes:

[0092] S201, obtain the current oscillation current of the oscillator;

[0093] S202, based on the preset relationship between vibratory current and formation density, find the formation density corresponding to the current vibratory current;

[0094] S203, the found formation density is determined as the current formation density.

[0095] like Figure 2 As shown, the vibrator 3 is connected to the controller 1 through the vibrator frequency converter cabinet 2. The vibrator frequency converter cabinet 2 and the controller 1 are connected wirelessly or wiredly.

[0096] In one embodiment of this example, when encountering a locally uniformly distributed stratum, the instantaneous value of the obtained oscillating current is stable. S201 obtains the current oscillating current of the oscillator in the following way: obtains the instantaneous value of the oscillating current of the oscillator; and determines the obtained instantaneous value of the oscillating current as the current oscillating current.

[0097] In this implementation, controller 1 obtains the vibration current signal of vibrator 3 from vibrator inverter cabinet 2 and determines the obtained vibration current as the current vibration current. Alternatively, a current detection sensor (not shown in the figure) is installed on the vibration output line of vibrator 3 connected to vibrator inverter cabinet 2; when vibrator 3 is started, the current detection sensor generates a vibration current signal, which is transmitted to controller 1 in real time via wired or wireless means. Controller 1 determines the vibration current transmitted from the current detection sensor in real time as the current vibration current. The current detection sensor can be any sensor capable of detecting current in the prior art, such as a current transformer.

[0098] In another embodiment of this example, when encountering locally unevenly distributed strata, the instantaneous values ​​of the acquired vibratory current jump significantly. S201 acquires the current vibratory current of the vibrator in the following way: acquire multiple instantaneous values ​​of the vibratory current; average the acquired multiple instantaneous values ​​of the vibratory current to obtain the average vibratory current; and determine the average vibratory current as the current vibratory current. The time interval between acquiring two adjacent instantaneous values ​​of the vibratory current is equal. The method for averaging the acquired multiple instantaneous values ​​of the vibratory current is as follows: n (n≥2) consecutively acquired instantaneous values ​​of the vibratory current are grouped into a queue, and the n instantaneous values ​​in the queue are summed and averaged; each newly acquired instantaneous value of the vibratory current is added to the tail of the queue, while the first instantaneous value of the vibratory current is removed, forming a new queue, and the n instantaneous values ​​in the new queue are summed and averaged.

[0099] In specific implementation, the method for obtaining the instantaneous value of the oscillation current is the same as that described in the previous implementation. Specifically, a current averaging module can be set up inside the controller. The controller obtains the instantaneous value of the oscillation current from the oscillator inverter cabinet 2 or the current detection sensor. The current averaging module averages the n (n≥2) instantaneous values ​​of the oscillation current in the queue to obtain the average oscillation current. The controller determines the average oscillation current as the current oscillation current.

[0100] Specifically, S202 searches for the formation density corresponding to the current vibratory current based on a preset correspondence between vibratory current and formation density; and S203 determines the found formation density as the current formation density. The specific implementation method is as follows:

[0101] The controller has a pre-set relationship between vibratory current and soil density. This relationship is obtained through testing. Before formal construction, test pile holes are drilled on site, and the controller analyzes the large amount of data obtained from these test pile holes to determine the relationship between the vibratory current and soil density.

[0102] In one embodiment of this study, the relationship between vibratory current and formation density is shown in Table 1. Formation density is divided into three levels: soft, medium, and hard. The relationship between different levels of formation density and vibratory current is obtained through field test data.

[0103] Table 1. Correspondence between vibratory current and formation density

[0104] Vibration current I Formation density Dr I<0.3Ie soft 0.3Ie <I<0.8Ie middle I>0.8Ie hard

[0105] In Table 1, Ie represents the rated current of the vibrator.

[0106] After obtaining the current vibration current, the controller determines the current formation density by looking up Table 1. For example, when the controller 1 obtains the current vibration current I = 0.3Ie, it determines the current formation density as medium by looking up Table 1.

[0107] It should be noted that Table 1 only shows one correspondence between the vibration current and the formation density. For more complex formations, the controller can obtain other more complex correspondences based on field test data.

[0108] Specifically, S102 acquires the instantaneous sewage pressure of the supplied sewage and determines the acquired instantaneous sewage pressure as the current sewage pressure. The specific implementation method is as follows:

[0109] like Figure 3 As shown, a water supply pressure detection sensor 41 is installed on the outlet pipe of the water pump 4 to obtain the instantaneous water pressure supplied by the water pump 4 and transmit it to the controller 1. The controller 1 determines the instantaneous water pressure transmitted from the water supply pressure detection sensor 41 as the current water pressure.

[0110] Because screw pumps have the characteristics of pulsation-free water supply pressure and stable instantaneous flow rate, this embodiment uses a screw pump to supply sewage. However, other pumps with pulsation-free water supply pressure and stable instantaneous flow rate can also be used, as long as the supplied sewage pressure and flow rate meet the requirements. A water supply pressure detection sensor 41 is installed on the outlet pipe of the screw pump to obtain the instantaneous sewage pressure supplied by the screw pump. The water supply pressure detection sensor 41 can be any sensor capable of detecting water pressure available in the prior art. For example, a pressure transmitter can be used.

[0111] In addition, such as Figure 3 As shown, a water supply flow detection sensor 42 is also installed on the outlet pipe of water pump 4 to detect the instantaneous flow rate of water supplied by water pump 4 in real time. The water supply flow detection sensor 42 can be any sensor capable of detecting water flow rate in the prior art. For example, an electromagnetic flow meter can be used. The water supply flow detection sensor 42 transmits the detected instantaneous flow rate of water supplied by water pump 4 to controller 1, and the controller determines the instantaneous flow rate as the current flow rate.

[0112] like Figure 3 As shown, the water supply pressure detection sensor 41 and the water supply flow detection sensor 42 transmit the real-time detected instantaneous water pressure signal and instantaneous water flow signal to the remote terminal unit (RTU), and the RTU transmits the signal to the controller 1 wirelessly.

[0113] Specifically, S103, based on the preset correspondence between groundwater pressure and formation density, finds the target groundwater pressure corresponding to the current formation density. The specific implementation method is as follows:

[0114] The controller has a pre-set correlation between water pressure and soil density. This correlation is obtained through testing; that is, before formal construction, test pile holes are drilled on site, and the controller analyzes the large amount of data obtained from the test pile holes to determine the correlation between water pressure and soil density.

[0115] In one embodiment of this example, the relationship between groundwater pressure and formation density is shown in Table 2. Formation density is divided into three levels: soft, medium, and hard. The relationship between different levels of formation density and groundwater pressure is obtained through field test data.

[0116] Table 2. Correspondence between groundwater pressure and formation density

[0117] Water pressure P (MPa) Formation density Dr 0.3～0.5 soft 0.5～0.7 middle 0.7～0.8 hard

[0118] Controller 1 uses lookup table 2 to find the target groundwater pressure corresponding to the current formation density. As shown in Table 2, upper and lower limits are set for the groundwater pressure corresponding to each level of formation density. For example, when controller 1 determines the current formation density to be medium using lookup table 1, it uses lookup table 2 to find the target groundwater pressure corresponding to the medium-level current formation density, which is 0.5–0.7 MPa.

[0119] It should be noted that Table 2 only shows one relationship between groundwater pressure and formation density. For more complex formations, the controller can obtain other more complex relationships based on field test data.

[0120] S104 controls the flow rate of the supplied sewage to make the current sewage pressure reach the target sewage pressure. The specific implementation method is as follows: compare the current sewage pressure and the target sewage pressure to obtain the difference between the current sewage pressure and the target sewage pressure; the controller controls the flow rate of the pump to supply sewage based on the difference between the current sewage pressure and the target sewage pressure to make the current sewage pressure reach the target sewage pressure.

[0121] Specifically, the controller controls the flow rate of water supplied by pump 4 based on the difference between the current drainage pressure and the target drainage pressure, including: when the current drainage pressure is greater than the upper limit of the target drainage pressure, controlling pump 4 to reduce the drainage flow rate; when the current drainage pressure is less than the lower limit of the target drainage pressure, controlling pump 4 to increase the drainage flow rate; and when the current drainage pressure is within the range of the target drainage pressure, controlling pump 4 to maintain the drainage flow rate.

[0122] like Figure 3 As shown, in this embodiment, the water pump 4 is connected to the controller 1 via the water pump frequency converter cabinet 5. The water pump frequency converter cabinet 5 and the controller 1 are connected wirelessly, but a wired connection can also be used. The controller 1 controls the speed of the water pump 4 by changing the output frequency of the water pump frequency converter cabinet 5, thereby changing the flow rate of the water supplied by the water pump 4. When the flow rate of the water discharged from the water pump outlet pipe increases, the water pressure also increases; when the flow rate of the water discharged from the water pump outlet pipe decreases, the water pressure also decreases.

[0123] This embodiment uses an SV-70 vibratory compactor for stone crushing piles. The telescopic guide rod connects to the vibratory compactor. The water control process is as follows:

[0124] 1. After the vibratory flusher 3 is started, the water supply pressure detection sensor 41 detects the instantaneous water pressure in real time, and the water supply flow detection sensor 42 detects the instantaneous water flow in real time.

[0125] 2. Controller 1 acquires the current vibration current, current drainage pressure, and current drainage flow rate;

[0126] 3. Controller 1 determines the current formation density corresponding to the current vibration current by looking up table 1; and determines the target groundwater pressure corresponding to the current formation density by looking up table 2.

[0127] 4. The controller 1 compares the current drainage pressure with the target drainage pressure, converts the difference signal into a control signal to control the output frequency of the water pump frequency converter cabinet 5, and changes the drainage flow rate of the water pump 4 by controlling the speed of the water pump 4, thereby changing the drainage pressure so that the current drainage pressure is within the target drainage pressure range.

[0128] After forming the crushed stone pile hole using the above method, the crushed stone pile hole is cleaned to ensure that the mud density inside the pile hole meets the requirements.

[0129] During the hole cleaning process, the mud density inside the crushed stone pile hole is obtained using a mud pump, including:

[0130] The mud pump is used to pump the mud from the crushed stone pile hole upwards to the mud density meter.

[0131] The density of the pumped mud is measured using a mud density meter to obtain the current mud density value inside the crushed stone pile hole.

[0132] In application, the mud density meter can be installed on the ground, such as on the outermost upper part of the telescopic guide rod, on the mast, or on the pile frame of the vibratory compactor. The mud pump can be lowered to the lower part of the stone pile hole via a winch, and the mud pump should be 2-3m above the bottom of the vibratory compactor (i.e., located in the middle of the vibratory compactor, 2-3m higher than the water outlet from the bottom of the vibratory compactor, and about 1-2m lower than the air outlet from the telescopic guide rod). Then, it should be synchronized with the vibratory compactor in terms of hole cleaning depth, and the mud pump used in the hole cleaning process should be sent to the mud density meter located on the ground through pipeline. Alternatively, the mud pump and mud density meter can be integrated into one unit and placed on the ground, such as on the upper outermost layer of the telescopic guide rod, the mast, or the pile frame of the vibratory stone crushing machine. During operation, the pipeline is sent into the lower part of the stone crushing pile hole through the winch device, and the mud pump is sent to the mud density meter located on the ground through the pipeline 2-3m above the bottom of the vibratory compactor.

[0133] When installing mud density meters and mud pumps, they can be connected to other components in a detachable manner so that they can be removed when mud density testing is not required.

[0134] The process involves obtaining the current mud density value inside the crushed stone pile hole using a mud density meter, and then controlling the flow rate of the supplied water and the flow rate of the supplied pressurized air based on the obtained mud density to ensure that the mud density inside the crushed stone pile hole meets the requirements. This includes:

[0135] After obtaining the current mud density value in the crushed stone pile hole, compare the current mud density value with the preset mud density threshold.

[0136] Based on the comparison between the current mud density value and the preset mud density threshold, the flow rate of the supplied water and the flow rate of the supplied pressurized air are controlled so that the mud density in the crushed stone pile hole meets the requirements.

[0137] Among them, such as Figure 10 As shown, based on the comparison between the current mud density value and the preset mud density threshold, the control of the sewage flow rate and the pressurized air flow rate includes:

[0138] When the comparison result shows that the current mud density value is within the preset mud density threshold, the vibratory compactor is moved up and down in the crushed stone pile hole (the range of movement is generally controlled within 2 meters), and the water pump and air pump are controlled to clean the pile hole at the current water flow rate and the current air flow rate.

[0139] When the comparison result shows that the current mud density value exceeds the preset mud density threshold, the flow rate of the supplied water and the flow rate of the supplied pressurized air are controlled so that the mud density value is within the preset mud density threshold.

[0140] The controller is pre-programmed with the correlation between the mud density in the crushed stone pile hole and different permeability crushed stone piles. This correlation is obtained through testing; that is, test pile holes are drilled on-site before formal construction, and the controller analyzes the extensive data obtained from these test holes to determine the correlation between the mud density and different permeability crushed stone piles. The preset mud density threshold is the mud density value corresponding to crushed stone piles that meet the preset permeability requirements.

[0141] In application, the preset mud density threshold is determined according to the actual construction conditions. For example, in this invention, the preset mud density threshold is less than or equal to 1.10 g / cm³. 3 .

[0142] The rated maximum water flow rate and rated maximum air flow rate are determined based on the vibratory compactor and the water and air pumps used in the vibratory compaction stone pile construction. The current water flow rate and current air flow rate are usually 70-75% of the rated maximum water flow rate and rated maximum air flow rate, respectively.

[0143] Specifically, when the comparison result shows that the current mud density value exceeds the preset mud density threshold, the flow rate of the supplied water and the flow rate of the supplied pressurized air are increased to 80-90% of the rated maximum water flow rate and rated maximum air flow rate, respectively. At the same time, the vibratory compactor is moved up and down (the range of movement is generally controlled within 2 meters) to reduce the mud density in the borehole to less than or equal to the preset mud density threshold.

[0144] If the mud density suddenly increases abnormally during the cleaning process of the crushed stone pile hole and lasts for more than 2 minutes, it indicates that there may be signs of local hole collapse. At this time, chemical mud wall protection treatment should be carried out on the crushed stone pile hole before continuing the hole cleaning.

[0145] The comprehensive treatment of crushed stone pile holes using chemical mud slurry for wall protection employs the following formula by weight: 0.5-2 parts polyacrylamide per 1000 parts water. Specifically, when chemical mud slurry wall protection is required, the volume of the crushed stone pile hole is taken as the required volume of water. The weight of the water corresponding to that volume is then calculated, and polyacrylamide is added to the water at a weight ratio of 0.5-2 parts per 1000 parts water. The higher the detected mud density inside the hole, the greater the probability of hole collapse, and therefore the more polyacrylamide is added.

[0146] This invention controls the mud density inside the crushed stone pile hole during the hole cleaning process, ensuring that the mud density inside the pile hole meets the requirements. This ensures that the permeability of the crushed stone pile formed after subsequent filling and vibratory compaction meets the preset requirements, so as to ensure that the crushed stone pile can vertically transmit the excess pore water pressure from deep strata to the crushed stone cushion layer under strong earthquake conditions, and that the vibratory compaction of the crushed stone pile does not break under strong earthquake conditions.

[0147] After the hole cleaning process is completed, the crushed stone filler is placed into the crushed stone pile hole in batches. The crushed stone filler placed into the crushed stone pile hole in batches is vibrated and compacted one by one by a vibratory compactor to form N crushed stone pile segments. Thus, through the N crushed stone pile segments, a continuous, uniform vibratory compacted crushed stone pile with an effective pile diameter is formed from bottom to top in the crushed stone pile hole.

[0148] In this invention, the effective pile diameter of the crushed stone pile refers to the pile diameter in which the crushed stone pile formed in the crushed stone pile hole is in close contact with the surrounding soil layer. The effective pile diameter of the crushed stone pile of this invention has the following significance:

[0149] First, the crushed stone pile formed in the crushed stone pile hole is tightly bonded to the soil layer around the hole;

[0150] Secondly, the effective pile diameter of the crushed stone pile is the pile diameter that meets the requirements of vibro-compaction densification. Therefore, it is not required to calculate the actual pile diameter during vibro-compaction construction, which speeds up the vibro-compaction construction process.

[0151] like Figure 6The diagram shown is a simplified structural diagram of the vibratory compactor used in the vibratory compactor pile machine of the present invention. The difference between the vibratory compactor 1000 of the present invention and the existing vibratory compactor is that a microphone 1311 for picking up sound and a support rod 1312 for fixing the microphone 1311 are installed inside the housing 1308 of the vibratory compactor. The support rod 1312 passes through the through hole of the bearing seat for supporting the shaft 1306 and is fixed to the housing of the motor 1304. Figure 6 The vibratory impactor 13 shown also includes a hanger 1301, a water pipe 1302, a cable 1303, a motor 1304, a coupling 1305, a shaft 1306, an eccentric block 1307, a housing 1308, fins 1309, a drain pipe 1310, and a microphone 1311.

[0152] After a batch of crushed stone filler is placed into the crushed stone pile hole, the vibratory compactor begins to compact the filler by energizing motor 1304. Under the excitation force of the vibratory compactor, the filler in the compaction section is squeezed horizontally into the original stratum, while the upper filler falls into the mud under its own weight. The filler height can be measured in real time. As the compaction process proceeds, the following phenomena occur:

[0153] First, the encryption current gradually increases;

[0154] Second, the excitation force at the vibratory impactor housing increases;

[0155] Third, the amplitude of the vibratory beater decreases accordingly;

[0156] Fourth, with the vibratory compactor as the center, the surrounding fill material gradually becomes denser, gradually forming a roughly circular vibratory crushed stone pile body with the highest density in the vibratory compactor's vibratory range, and the lateral pressure that can be provided by the original stratum when it reaches the periphery of the pile hole is basically equivalent to that provided by the original stratum.

[0157] Existing technologies mainly control the densification of crushed stone packing based on the densification current of motor 1304, but they have the following four problems:

[0158] First, the physical and engineering significance is unclear, and there is no direct relationship between it and the density. The magnitude of the densification current needs to be determined experimentally, and the density data of the pile body can only be roughly obtained after the experiment. However, when the depth of the vibratory compaction stone pile is as high as 70m or even reaches the level of 100m, the density data of the pile body cannot be obtained through traditional experiments at this depth, and therefore the densification current cannot be determined experimentally.

[0159] Second, different models and power oscillators have different currents in different strata;

[0160] Third, from an engineering practice perspective, even vibratory beaters from the same manufacturer and of the same model can have significantly different no-load currents.

[0161] Fourth, in colder regions, the no-load current of the vibratory compactor is relatively large when it is first used; however, as the project progresses, the temperature of the vibratory compactor itself increases, and the no-load current decreases accordingly.

[0162] Therefore, using the densification current as a measure of compactness cannot characterize the compactness of piles under ultra-deep overburden conditions.

[0163] To address the aforementioned problems in the prior art, this invention proposes a technique for controlling the vibratory compactor to perform vibratory compaction (i.e., vibratory compaction of the crushed stone packing) based on the vibration signal frequency of the vibratory compactor during the compaction of the crushed stone packing. The core technology of this compaction technique is:

[0164] During the process of vibratory compactor 13 vibrating the crushed stone filling around it, a microphone set inside the vibratory compactor housing is used to detect the real-time vibration signal of the vibratory compactor when it vibrates the crushed stone embedded in the soil layer around the crushed stone pile hole.

[0165] Based on the real-time vibration signal of the vibratory compactor detected by the microphone located inside the vibratory compactor housing, the vibratory compactor is controlled to vibrate the crushed stone pile, so that the diameter of the crushed stone pile formed by the vibratory compactor filling the crushed stone pile hole is equal to the effective pile diameter.

[0166] The present invention controls the vibration of the vibratory compactor on the crushed stone pile based on the real-time vibration signal of the vibratory compactor detected by the microphone 1311 located inside the vibratory compactor housing, including:

[0167] By converting the real-time vibration signal of the oscillator detected by the pickup into the frequency domain, the main frequency of the real-time vibration signal of the oscillator is obtained.

[0168] Compare the main frequency of the real-time vibration signal of the vibratory impactor with a preset frequency;

[0169] When the main frequency of the real-time vibration signal of the vibratory compactor reaches or approaches the preset frequency, it is determined that the diameter of the crushed stone pile to be formed is equal to the effective pile diameter, and the vibratory compactor is lifted upward to vibrate and compact the crushed stone in the middle part of the crushed stone pile to be formed, thereby finally forming a crushed stone pile with a pile diameter equal to the effective pile diameter.

[0170] When the main frequency of the real-time vibration signal of the vibratory compactor is greater than the preset frequency, the vibratory compactor is controlled to continue vibrating the crushed stone embedded in the soil layer around the crushed stone pile hole.

[0171] The preset frequency of the present invention is the main frequency of the vibrator vibration signal when the vibrator amplitude is reduced to the minimum.

[0172] The present invention controls the vibration of the vibratory compactor on the crushed stone pile based on the real-time vibration signal of the vibratory compactor detected by a microphone located inside the vibratory compactor housing, including:

[0173] By converting the vibration signal of the front vibrator detected by the microphone in front and the vibration signal of the rear vibrator detected behind into the frequency domain, the main frequency of the vibration signal of the front vibrator and the main frequency of the vibration signal of the rear vibrator are obtained.

[0174] The dominant frequencies of the vibration signals of the preceding and following vibratory impactors were analyzed during the vibration period.

[0175] When the main frequency of the vibration signal of the rear vibratory compactor is lower than that of the main frequency of the vibration signal of the front vibratory compactor and remains so for a period of time, it is determined that the diameter of the crushed stone pile to be formed is equal to the effective pile diameter. The vibratory compactor is then raised to vibrate and compact the crushed stone in the middle part of the crushed stone pile to be formed, thus ultimately forming a crushed stone pile with a pile diameter equal to the effective pile diameter.

[0176] The microphone of the present invention, located inside the housing of the vibrator, includes a sound sensor and an audio amplifier.

[0177] The microphone disposed inside the housing of the vibrator in this invention can also be a sound sensor.

[0178] Figure 7 The control section shown is used to control the vibratory compactor to vibrate and densify the crushed stone filler. It includes a microphone 1311 for converting the vibration signal on the vibratory compactor housing into a corresponding electrical signal, an audio analysis module for performing audio analysis on the electrical signal output by the microphone 1311, a processor for processing the audio output by the audio analysis module, a memory for storing the data output by the processor, and a display for displaying the data output by the processor.

[0179] In addition, the processor is connected to the main winch so that when it is determined that the diameter of the crushed stone pile to be formed is equal to the effective pile diameter, the vibratory compactor 13 is lifted upward.

[0180] The microphone 1311 of the present invention may include a sound sensor and an audio amplifier, or it may include only a sound sensor.

[0181] The audio analysis module, processor, memory, and display of this invention can be installed on the ground, and the audio analysis module can be connected to the microphone via a cable. Furthermore, the audio analysis module of this invention can be a Fourier transform to convert the vibration signal from the time domain to the frequency domain.

[0182] Compared to another patent application filed by the inventor regarding a pressure sensor mounted on the housing of a vibratory compactor, this invention can significantly extend the service life of the sound sensor. In other words, because the sound sensor 1311 is mounted inside the housing of the vibratory compactor, it is not subject to the pressure from the gravel packing and the vibrator, unlike the pressure sensor mounted on the housing, and is therefore less prone to damage.

[0183] Figure 8 The control flow of a first embodiment of controlling a vibratory oscillator for vibration encryption control is shown. This flow is mainly implemented by a processor and specifically includes:

[0184] Step S301: During the vibratory compactor's vibration of the crushed stone packing, the microphone detects the real-time vibration signal of the vibratory compactor housing.

[0185] Step S302: By converting the real-time vibration signal of the oscillator detected by the pickup into the frequency domain, the main frequency of the real-time vibration signal of the oscillator is obtained.

[0186] Step S303: Determine whether the main frequency of the real-time vibration signal of the vibratory impactor has reached or is close to the preset frequency.

[0187] Step S304: If the judgment result of step S302 is yes, determine that the diameter of the crushed stone pile to be formed is equal to the effective pile diameter.

[0188] Step S305: Raise the vibratory compactor upwards to vibrate and compact the crushed stone in the middle part of the vibratory crushed stone pile to form a crushed stone pile with a pile diameter equal to the effective pile diameter.

[0189] Step S306: If the judgment result of step S302 is negative, control the vibratory compactor to continue vibrating the crushed stone embedded in the soil layer around the crushed stone pile hole.

[0190] Figure 9 The control flow of a second embodiment for controlling the vibratory oscillator to perform vibration encryption control is shown, including:

[0191] Step S401: During the vibratory compaction of the crushed stone packing, the microphone detects the real-time vibration signal of the vibratory compactor housing to obtain the vibration signal of the front vibratory compactor detected by the microphone and the vibration signal of the rear vibratory compactor detected by the microphone.

[0192] Step S402: By converting the vibration signal of the front oscillator detected by the microphone in front and the vibration signal of the rear oscillator detected behind into the time domain to the frequency domain, the main frequency of the vibration signal of the front oscillator and the main frequency of the vibration signal of the rear oscillator are obtained.

[0193] Step S403: Determine whether the main frequency of the vibration signal of the rear vibrator is less than the main frequency of the vibration signal of the front vibrator.

[0194] Step S404: If the judgment result of step S403 is yes, then further determine whether the main frequency of the vibration signal of the vibrator detected later remains unchanged for a period of time.

[0195] Step S405: If the judgment result of step S404 is yes, then it is determined that the diameter of the crushed stone pile to be formed is greater than or equal to the effective pile diameter.

[0196] Step S405: Raise the vibratory compactor upwards to vibrate and compact the crushed stone in the middle part of the vibratory crushed stone pile to be formed, thereby finally forming a crushed stone pile with a pile diameter greater than or equal to the effective pile diameter.

[0197] Step S406: If the judgment result of step S403 or step S404 is negative, then control the vibratory compactor to continue vibrating the crushed stone embedded in the soil layer around the crushed stone pile hole.

[0198] It should be noted that one of the features of this invention is the introduction of the concept of effective pile diameter, which is the pile diameter of the crushed stone pile formed in the crushed stone pile hole that is tightly bonded to the soil layer around the hole and meets the requirements of vibratory compaction.

[0199] The effective pile diameter of the crushed stone pile of the present invention solves the technical problem that the crushed stone pile may not be able to bond tightly with the soil layer in the prior art.

[0200] Although the present invention has been described in detail above, the present invention is not limited thereto. Those skilled in the art can make modifications based on the principles of the present invention. Therefore, all modifications made in accordance with the principles of the present invention should be understood as falling within the protection scope of the present invention.

Claims

1. A method for controlling the permeability of vibratory compaction stone piles, comprising: By controlling the water launch of the vibratory compaction stone pile machine, which includes telescopic guide rods and vibratory compactors, the vibratory compaction construction of the stone pile hole with stone filling can be completed quickly. The holes of the crushed stone piles are cleaned, and the mud density inside the holes is obtained by using a mud pump that is synchronized with the vibratory compactor in depth during the cleaning process. The flow rate of the water supplied and the flow rate of the air supplied are controlled according to the mud density obtained by the mud pump, so that the mud density in the crushed stone pile hole meets the requirements. Continue the hole cleaning process with the required mud density until the hole cleaning process is completed; After the hole cleaning is completed, crushed stone filler is placed into the crushed stone pile hole, and a vibratory compactor is used to compact the crushed stone filler in the hole to form a vibratory compacted crushed stone filler pile with an effective pile diameter. This includes: during the vibratory compaction of the crushed stone filler in the hole, a microphone installed inside the vibratory compactor housing is used to detect the real-time vibration signal of the vibratory compactor when it compacts the crushed stone filler embedded in the soil layer around the crushed stone pile hole; based on the real-time vibration signal detected by the microphone inside the vibratory compactor housing, the vibratory compaction of the crushed stone filler pile by the vibratory compactor is controlled so that the diameter of the crushed stone filler pile formed by the vibratory compactor compacting the crushed stone filler into the crushed stone pile hole is equal to the effective pile diameter.

2. The method according to claim 1, wherein obtaining the mud density inside the crushed stone pile hole during the hole cleaning process using a mud pump includes: The mud pump is used to pump the mud from the crushed stone pile hole upwards to the mud density meter. The density of the pumped mud is measured using a mud density meter to obtain the current mud density value inside the crushed stone pile hole.

3. The method according to claim 2, wherein the mud density meter is installed on the ground.

4. The method according to claim 2 or 3, wherein controlling the flow rate of the supplied water and the flow rate of the supplied air based on the obtained mud density, so that the mud density in the crushed stone pile hole meets the requirements, includes: After obtaining the current mud density value in the crushed stone pile hole, compare the current mud density value with the preset mud density threshold. Based on the comparison between the current mud density value and the preset mud density threshold, the flow rate of the supplied water and the flow rate of the supplied air are controlled so that the mud density in the crushed stone pile hole meets the requirements.

5. The method according to claim 4, wherein controlling the flow rate of the supplied sewage and the flow rate of the supplied gas based on a comparison between the current mud density value and a preset mud density threshold comprises: The comparison result is that when the current mud density value is within the preset mud density threshold, the hole cleaning process is controlled at the current water flow rate and the current air flow rate. The comparison result is that when the current mud density value exceeds the preset mud density threshold, the flow rate of the supplied water and the flow rate of the supplied air are controlled so that the mud density value is within the preset mud density threshold.

6. According to the method of claim 5, when the comparison result shows that the current mud density value exceeds the preset mud density threshold, if a hole collapse occurs during the process of controlling the flow rate of the supplied water and the flow rate of the supplied air, chemical mud wall protection treatment is performed on the crushed stone pile hole.

7. The method according to claim 1, wherein controlling the launching of the vibratory compaction pile machine including the telescopic guide rod and the vibratory compactor to quickly complete the vibratory compaction construction of the crushed stone pile hole includes: The pipe used to supply sewage passes through the telescopic guide rod and the vibratory flusher and extends from the bottom of the vibratory flusher so that the sewage is sprayed out from the bottom of the vibratory flusher to pre-damage the formation with water. Obtain the current formation density during vibro-compaction construction; Obtain the instantaneous drainage pressure of the supplied water and determine the obtained instantaneous drainage pressure as the current drainage pressure; Based on the preset correspondence between groundwater pressure and formation density, find the target groundwater pressure corresponding to the current formation density; Control the flow rate of the supplied water to bring the current water pressure to the target water pressure, so as to complete the vibratory compaction of the crushed stone pile hole by using the vibratory compactor and the target water pressure.

8. The method according to claim 7, wherein obtaining the current formation density comprises: Obtain the current oscillation current of the oscillator; Based on the preset relationship between vibratory current and formation density, find the formation density corresponding to the current vibratory current. The found formation density is determined as the current formation density.

9. The method according to claim 8, wherein obtaining the current pulse current of the oscillator comprises: Obtain the instantaneous value of the vibration current of the vibrator; The instantaneous value of the acquired oscillation current is determined as the current oscillation current.

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