Liquid-state conversion jet grouting method
By drilling from top to bottom by drilling rigs and opening the nozzle at the second soil strata for liquefaction, the problem of poor water stopping of rotary spray piles in complex formations is solved, and the uniform cement content and construction safety are improved.
Patent Information
- Application Number
- CN202510359559.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2025-05-13
AI Technical Summary
During construction, for complex strata such as silty sand, silt, silt, and silt, conventional bottom-up spin spraying operations can easily lead to uneven cement content of piles, mud blocks, local broken piles and landslides, which seriously affects the water stop effect of spin spraying piles.
Drilling from the surface from top to bottom through the drilling rig, the drill rod drives the nozzle to move vertically downward. When the nozzle is located in the second soil strata, the nozzle is turned on, the nozzle starts to spray the slurry, and the drill rod rotates, so that the second soil strata forms a liquefied soil layer to ensure that the material distribution is more uniform.
Through the formation of liquefied soil layer, the uneven cement content of the pile body in the depth direction is avoided, the phenomenon of mud clamping and local pile breaking is reduced, and the risk of landslide is reduced, thereby improving the water-stop effect of the rotary spray pile.
Smart Images
Figure CN119981069A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of jet grouting pile construction, and in particular to a liquid conversion jet grouting method. Background Art
[0002] Jet-jet piles use a drilling rig to place the jet-jet grouting pipe and nozzle at the designed elevation of the pile bottom. After the pre-prepared slurry is passed through a high-pressure generator to give the liquid flow huge energy, it is ejected at high speed from the nozzle on the side of the grouting pipe, forming a highly energy-concentrated liquid flow that directly destroys the soil. During the injection process, the drill rod rotates and lifts to fully mix the slurry and the soil, forming a columnar consolidation body of a certain diameter in the soil, thereby strengthening the foundation. The construction is generally divided into two work processes, namely, drilling first and then spraying, then drilling and spraying, and then lifting and stirring to ensure the slurry-soil ratio and quality per meter of pile.
[0003] At present, in actual projects, for strata such as pebble strata (recorded as the first soil stratum), high-pressure jet grouting piles can be used, and the rotary jetting operation can be completed from bottom to top; however, for complex strata such as silty sand, silt, silt, etc. (recorded as the second soil stratum), conventional rotary jetting operations are carried out from bottom to top. Because the soil of such strata is loose, the adhesion is low, the texture distribution is uneven, or there are faults when the strata are formed, the water-stop curtain piles formed during construction in such strata usually have uneven cement content in the depth direction of the pile body, and there are often mud blocks, local broken piles, and even landslides, which seriously affect the water-stopping effect of the rotary jet piles. Summary of the invention
[0004] In view of the defects existing in the prior art, the technical problem solved by the present invention is: how to improve the water-stopping effect of rotary jet grouting piles.
[0005] To achieve the above purpose, the liquid conversion rotary spraying method provided by the present invention comprises the following steps: Obtaining distribution information of soil strata, wherein the soil strata include a second soil stratum; Drilling is performed at a preset position on the surface by a drilling rig, and the drill rod of the drilling rig drives the sprinkler head to move vertically downward. When the sprinkler head is located at the second soil layer, the sprinkler head is turned on, otherwise, the sprinkler head is turned off, so that the second soil layer forms a liquefied soil layer until the sprinkler head reaches the designed elevation of the pile bottom; The sprinkler head is turned on, and the drill rod drives the sprinkler head to move vertically upward until the sprinkler head reaches the designed elevation of the pile top to form a jet jet pile.
[0006] By adopting the above technical scheme, a liquefied soil layer is formed in the second soil stratum. The liquefied soil layer is a liquid mixture of multiple second soil strata, and the material distribution in the liquid mixture is more even due to stirring. Therefore, when the rotary jet grouting operation is carried out from bottom to top, the formed water-stop curtain piles are avoided, which usually have uneven cement content in the depth direction of the pile body, and often have the phenomenon of mud blocks, partial broken piles, and even landslides. The water-stopping effect of the rotary jet piles is improved.
[0007] In one embodiment, when the sprinkler is located in the second soil layer, turning on the sprinkler specifically includes: According to the distribution information of the second soil stratum; If the second soil layer has one layer; When the nozzle moves vertically downward and reaches a first threshold, the nozzle of the nozzle starts to spray, and the drill rod drives the nozzle to rotate until the nozzle moves vertically downward and reaches a second threshold.
[0008] By adopting the above technical solution, when there is only one second soil layer in the soil layer at the preset position, it is only necessary to set an interval range. When the sprinkler enters this interval range, the nozzle of the sprinkler starts to spray, and the drill rod drives the nozzle to rotate, so that the second soil layer forms a liquefied soil layer.
[0009] In one embodiment, when the sprinkler is located in the second soil layer, turning on the sprinkler specifically includes: According to the distribution information of the second soil stratum; If the second soil stratum has multiple layers; When the nozzle moves vertically downward and reaches the third threshold, the nozzle of the nozzle starts to spray, and the drill rod drives the nozzle to rotate until the nozzle moves vertically downward and reaches the fourth threshold; When the sprinkler head moves vertically downward and reaches the fifth threshold, the nozzle of the sprinkler head starts spraying, and the drill rod drives the nozzle to rotate until the sprinkler head moves vertically downward and reaches the sixth threshold; Repeat the above operation until all the second soil strata form liquefied soil layers.
[0010] By adopting the above technical solution, when there are multiple layers of second soil strata in the soil strata at the preset position, multiple interval ranges need to be set, and the number of interval ranges is the same as the number of layers of the second soil strata, so that all the second soil strata form liquefied soil layers, thereby ensuring the water-stopping effect of the rotary jet piles.
[0011] In one embodiment, the construction method further comprises: The soil layer between the ground surface and the design elevation of the pile top is recorded as the surface layer; When the bottom of the surface layer is the second soil stratum, an anti-collapse member is arranged between the surface layer and the second soil stratum.
[0012] By adopting the above technical solution, the first function of the surface layer is to ensure the verticality of the drill rod moving downward, and the second function is to prevent waste slurry from seeping into the pile body; the anti-collapse parts prevent the bottom of the surface layer from collapsing into the liquefied soil layer.
[0013] In one embodiment, the soil stratum further comprises a first soil stratum; When the bottom of the first soil stratum is the second soil stratum, an anti-collapse member is arranged between the first soil stratum and the second soil stratum.
[0014] By adopting the above technical solution, the anti-collapse member prevents the bottom of the first soil layer from collapsing into the liquefied soil layer.
[0015] In one embodiment, the anti-slump member is an inverted funnel.
[0016] By adopting the above technical solution, in view of the situation that the above two boundary parts are prone to collapse, the anti-collapse principle of the arched dome is utilized to avoid the occurrence of collapse.
[0017] In one embodiment, an inverted funnel is provided, specifically comprising: When the drill rod of the drilling rig drives the sprinkler head to move vertically downward; When the sprinkler head reaches the designed elevation of the top of the inverted funnel, the nozzle of the sprinkler head starts to spray, and the drill rod drives the nozzle to rotate until the sprinkler head reaches the designed elevation of the bottom of the inverted funnel, forming an inverted funnel.
[0018] By adopting the above technical solution, while the drill rod drives the sprinkler head to move vertically downward, the inverted funnel can be built simultaneously, thereby improving the efficiency of the jet grouting pile construction.
[0019] In one embodiment, the nozzle of the nozzle starts spraying, and the drill rod drives the nozzle to rotate, specifically including: The nozzle sprays at a preset initial pressure and a preset pressure gradient; When the spray pressure of the nozzle reaches the preset maximum pressure, the nozzle reaches the designed elevation of the bottom of the inverted funnel; The injection pressure of the nozzle becomes a pressure that causes the second soil layer to form a liquefied soil layer.
[0020] By adopting the above technical solution, the slope of the inverted funnel is made smoother and more regular, thereby further improving the anti-collapse effect.
[0021] In one embodiment, the top of the inverted funnel is designed to be at the surface layer, and the bottom of the inverted funnel is designed to be at the second soil layer; And / or, the design elevation of the top of the inverted funnel is located at the first soil stratum, and the design elevation of the bottom of the inverted funnel is located at the second soil stratum.
[0022] By adopting the above technical solution, the inverted funnel can be prevented from falling into the liquefied soil layer. Therefore, the top of the inverted funnel needs to be embedded in the surface layer or the first soil stratum to give the inverted funnel an upward pulling force. The third function of the surface layer is to fix the inverted funnel. At the same time, it is necessary to avoid the collapse of the bottom surface of the surface layer or the first soil stratum. Therefore, the bottom of the inverted funnel needs to be lower than the bottom surfaces of the two, thereby playing an anti-collapse role.
[0023] In one embodiment, the diameter of the drill rod is 375 mm or 433 mm, the material of the drill rod is 27 silicon manganese steel or 40 molybdenum, and the wall thickness of the drill rod is not less than 25 mm.
[0024] By adopting the above technical solution, the spraying work of the nozzle during the movement from top to bottom is avoided. The reaction force of the nozzle causes the nozzle and the drill rod to deviate. Therefore, the above design can further ensure the verticality of the construction.
[0025] In summary, the present invention includes at least one of the following beneficial technical effects: 1. Drilling is performed from the surface from top to bottom by a drilling rig until the designed elevation of the pile bottom is reached. During drilling, the drill rod of the drilling rig drives the sprinkler head from the surface to the designed elevation of the pile bottom. In the process of the sprinkler head moving downward, as long as it passes through the second soil layer, the sprinkler head starts to work, that is, the nozzle of the sprinkler head starts to spray slurry, and the rotation of the drill rod drives the nozzle to rotate, so that the slurry is sprayed into the second soil layer. At the same time, the surroundings of the second soil layer close to the drill rod are stirred to form a liquefied soil layer in the second soil layer there. The liquefied soil layer is a liquid mixture of multiple second soil layers, and the material distribution in the liquid mixture is more uniform due to stirring. Therefore, when performing the rotary spraying operation from bottom to top, the uneven cement content of the formed water-stop curtain pile in the depth direction is avoided, and the phenomenon of mud blocks, partial pile breakage, and even landslides often occur, thereby improving the water-stopping effect of the rotary spraying pile; 2. Through the design and construction method of the surface layer, it plays three roles: first, it ensures the verticality of the drill rod moving downward; second, it prevents the waste slurry from seeping into the pile body; and third, it fixes the inverted funnel; 3. The inverted funnel design avoids the collapse of the surface layer and the first soil layer into the liquefied soil layer at the boundary between different soil layers due to the fluidity of the liquefied soil layer, which affects the quality of the jet grouting piles, thereby further improving the water-stopping effect of the jet grouting piles. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 It is a flow chart of the liquid state conversion rotary spraying method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the first scenario of an embodiment of the present invention; Figure 3 It is a structural diagram of the second scenario of an embodiment of the present invention.
[0027] In the figure: 1 - first soil layer, 2 - second soil layer, 3 - surface layer, 4 - inverted funnel, 5 - borehole. DETAILED DESCRIPTION
[0028] The embodiments of the present invention are further described in detail below with reference to the accompanying drawings.
[0029] The liquid state conversion rotary spraying method in the embodiment of the present invention is shown in Figure 1 As shown, the liquid conversion rotary spraying method comprises the following steps: Before construction, the distribution information of soil strata is obtained by collecting and analyzing the address survey data, wherein the soil strata include the second soil stratum 2, and the distribution information includes the distribution, thickness, physical properties, etc. of different soil strata; For example, for a construction site with multiple strata, geological surveys show that the 0-10m layer is a silty sand layer, the 10-15m layer is a pebble layer, and the 15-20m layer is a silty fine sand layer. The pile top design elevation is -5m, and the pile bottom design elevation is -18m. A drilling rig is used to drill at a preset position on the surface to form a borehole 5, and the drill rod of the drilling rig drives the sprinkler head to move vertically downward. When the sprinkler head is located at the second soil layer 2, the sprinkler head is turned on and the drill rod drives the sprinkler head to rotate. Otherwise, the sprinkler head is turned off and the drill rod stops rotating, so that a liquefied soil layer is formed in the second soil layer 2 until the sprinkler head reaches the designed elevation of the pile bottom; The sprinkler head is turned on, and the drill rod drives the sprinkler head to rotate and move vertically upward until the sprinkler head reaches the designed elevation of the pile top to form a rotary jet pile.
[0030] It can be seen that the present invention uses a drilling rig to drill from the ground from top to bottom until the pile bottom design elevation is reached. While drilling, the drill rod of the drilling rig drives the nozzle from the ground surface to the pile bottom design elevation. In the process of the nozzle moving downward, as long as it passes through the second soil layer 2, the nozzle starts to work, that is, the nozzle of the nozzle starts to spray slurry, and the rotation of the drill rod drives the nozzle to rotate, so that the slurry is sprayed into the second soil layer 2. At the same time, the second soil layer 2 is stirred around the drill rod to form a liquefied soil layer in the second soil layer 2 there. The liquefied soil layer is a liquid mixture of multiple second soil layers 2, and the material distribution in the liquid mixture is more uniform due to stirring. Therefore, when the rotary spraying operation is performed from bottom to top, the formed water-stop curtain pile is avoided. The cement content of the pile body in the depth direction is usually uneven, and there are often mud blocks, local pile breakage, and even landslides. The water-stopping effect of the rotary spraying pile is improved.
[0031] It should be noted that the speed at which the drill rod drives the nozzle to move vertically downward is faster than the speed at which the drill rod drives the nozzle to move vertically upward during the construction of rotary jet piles from bottom to top. Therefore, it is necessary to form a liquefied soil layer into the second soil layer 2. At the same time, in order to save materials, when the second soil layer 2 is formed into a liquefied soil layer, the slurry sprayed from the nozzle is made of bentonite instead of cement.
[0032] Preferably, when the sprinkler is located at the second soil layer 2, turning on the sprinkler specifically includes: According to the distribution information of the second soil layer 2; If the second soil layer 2 has a layer; When the nozzle moves vertically downward and reaches a first threshold, the nozzle of the nozzle starts to spray, and the drill rod drives the nozzle to rotate until the nozzle moves vertically downward and reaches a second threshold.
[0033] Specifically, according to the obtained distribution information of the soil strata, the top and bottom elevations of the second soil stratum 2 can be known. Therefore, the top elevation is positioned at the first threshold, and the bottom elevation is positioned at the second threshold. When the moving distance of the sprinkler reaches the first threshold, that is, the sprinkler moves to the top surface of the second soil stratum 2, the nozzle of the sprinkler starts to spray, and the drill rod drives the nozzle to rotate; when the moving distance of the sprinkler reaches the second threshold, that is, the sprinkler moves to the bottom surface of the second soil stratum 2, indicating that the sprinkler is about to leave the second soil stratum 2, the nozzle of the sprinkler stops spraying, and the drill rod stops rotating; thereby realizing the rotational spraying and stirring from top to bottom of the second soil stratum 2, thereby forming a liquefied soil layer.
[0034] Preferably, in one embodiment, when the sprinkler is located at the second soil layer 2, turning on the sprinkler specifically includes: According to the distribution information of the second soil layer 2; If the second soil layer 2 has multiple layers; When the nozzle moves vertically downward and reaches the third threshold, the nozzle of the nozzle starts to spray, and the drill rod drives the nozzle to rotate until the nozzle moves vertically downward and reaches the fourth threshold; When the sprinkler head moves vertically downward and reaches the fifth threshold, the nozzle of the sprinkler head starts spraying, and the drill rod drives the nozzle to rotate until the sprinkler head moves vertically downward and reaches the sixth threshold; The above operation is repeated until all the second soil layers 2 form liquefied soil layers.
[0035] Specifically, according to the obtained soil stratum distribution information, the top and bottom elevations of the second soil stratum 2 can be known, so the top elevation is positioned at the third threshold and the fifth threshold, and the bottom elevation is positioned at the fourth threshold and the sixth threshold. When the moving distance of the sprinkler reaches the third threshold, that is, the sprinkler moves to the top surface of the second soil stratum 2, the nozzle of the sprinkler starts to spray, and the drill rod drives the nozzle to rotate; when the moving distance of the sprinkler reaches the fourth threshold, that is, the sprinkler moves to the bottom surface of the second soil stratum 2, it means that the sprinkler is about to leave the second soil stratum 2, and the sprinkler starts to spray. The nozzle of the nozzle stops spraying, and the drill rod stops rotating; the drill rod continues to drive the nozzle to move downward; when the moving distance of the nozzle reaches the fifth threshold, that is, the nozzle moves to the top surface of the second soil layer 2, the nozzle of the nozzle starts spraying, and the drill rod drives the nozzle to rotate; when the moving distance of the nozzle reaches the sixth threshold, that is, the nozzle moves to the bottom surface of the second soil layer 2, indicating that the nozzle is about to leave the second soil layer 2, the nozzle of the nozzle stops spraying, and the drill rod stops rotating; and so on, until the entire second soil layer 2 forms a liquefied soil layer. Thus, the entire second soil layer 2 is jetted and stirred from top to bottom, thereby forming a liquefied soil layer, ensuring the water-stopping effect of the jet-jet pile.
[0036] Preferably, the construction method further comprises: The soil layer between the ground surface and the pile top design elevation is recorded as surface layer 3; When the bottom of the surface layer 3 is the second soil stratum 2 (the first boundary scenario), an anti-collapse member is arranged between the surface layer 3 and the second soil stratum 2 .
[0037] Specifically, when the drilling rig drills from a preset position on the surface, only one hole is opened in the surface layer 3, the nozzle is in a closed state, and an anti-collapse component is set between the surface layer 3 and the second soil layer 2 to prevent the bottom of the surface layer 3 from collapsing into the liquefied soil layer.
[0038] The first function of the surface layer 3 is to ensure the verticality of the drill pipe moving downwards, because: When the bottom of the surface layer 3 is the second soil stratum 2, the second soil stratum 2 has formed a liquefied soil layer through the backjetting method (the drill rod drives the nozzle to move from top to bottom and rotates to spray slurry). The lateral restraint force of the liquefied soil layer on the drill rod is greatly reduced, resulting in a large swing of the drill rod during the backjetting construction, which causes a large vertical deviation when the rotary jet pile is made. Therefore, it is necessary to limit the drill rod through the hole opened inside the surface layer 3 to provide lateral restraint for the drill rod.
[0039] The second function of the surface layer 3 is to prevent waste slurry from penetrating into the pile body, because: During the backjetting operation, the second soil stratum 2 forms a liquefied soil layer. When the rotary jet pile construction is carried out from bottom to top, the waste slurry in the liquefied soil layer will be discharged from the hole because there is no constraint on the upper part. In this process, a large amount of waste slurry will penetrate into the pile body, reducing the quality of the pile body and causing poor pile formation effect. Therefore, the waste slurry is blocked by the surface layer 3 on the upper part of the liquefied soil layer to prevent the waste slurry from penetrating into the pile body.
[0040] Preferably, the soil stratum further comprises a first soil stratum 1; When the bottom of the first soil stratum 1 is the second soil stratum 2 (the second boundary scenario), an anti-collapse member is arranged between the first soil stratum 1 and the second soil stratum 2 .
[0041] Specifically, when the drilling rig is drilling inside the first soil layer 1, only one hole is opened in the first soil layer 1, the nozzle is in a closed state, and an anti-collapse component is set between the first soil layer 1 and the second soil layer 2 to prevent the bottom of the first soil layer 1 from collapsing into the liquefied soil layer.
[0042] Preferably, a specific structure of an anti-slump member is provided: The anti-collapse member is an inverted funnel 4 .
[0043] Specifically, in view of the situation that collapse is prone to occur in the above two boundary scenes, the anti-collapse principle of the arched dome is used to avoid the occurrence of collapse.
[0044] It should be noted that the reason why the first soil layer 1 is not subjected to back-spraying construction is that: When the backjet method is used in the first soil stratum 1 such as the pebble layer and the gravel layer, the fine particles will be brought out of the hole due to the lifting displacement effect in the jetting principle, but the large particles such as pebbles and gravel are concentrated at the bottom of the hole, resulting in increased jetting resistance or drill holding, which affects the water-stopping effect.
[0045] Further, an inverted funnel 4 is provided, which specifically comprises: When the drill rod of the drilling rig drives the sprinkler head to move vertically downward; When the sprinkler head reaches the designed elevation of the top of the inverted funnel, the nozzle of the sprinkler head starts to spray, and the drill rod drives the nozzle to rotate until the sprinkler head reaches the designed elevation of the bottom of the inverted funnel, forming an inverted funnel 4.
[0046] Specifically, while the drill rod drives the sprinkler head to move vertically downward, the inverted funnel 4 can be built simultaneously, thereby improving the efficiency of the jet grouting pile construction.
[0047] Further, the nozzle of the sprinkler head starts to spray, and the drill rod drives the nozzle to rotate, specifically including: The nozzle sprays at a preset initial pressure and a preset pressure gradient; When the spray pressure of the nozzle reaches the preset maximum pressure, the nozzle reaches the designed elevation of the bottom of the inverted funnel; The injection pressure of the nozzle becomes a pressure at which the second soil layer 2 forms a liquefied soil layer.
[0048] Specifically, the slope of the inverted funnel 4 is made smoother and more regular, thereby further improving the anti-collapse effect.
[0049] For the first scenario, the construction process is as follows: 1. No jet grouting is performed within the designed elevation range from the ground surface to the top of the inverted funnel, only drilling is performed; 2. When the top of the inverted funnel is reached, the jetting is started from top to bottom. The drilling speed of the drill is adjusted to 20cm / min, the initial pressure is preset to 5MPa, and the pressure gradient is preset to increase by 3MPa per minute, so as to gradually increase the jetting pressure; 3. When the injection pressure reaches 35 MPa, the injection pressure is restored to normal parameters for reverse injection construction, and a 2m high inverted funnel 4 can be formed.
[0050] For the second scenario, the construction process is as follows: 1. After entering the first soil layer, do not perform jet grouting, only drill down; 2. When the top of the inverted funnel is reached, the jetting is started from top to bottom. The drilling speed of the drill is adjusted to 20cm / min, the initial pressure is preset to 5MPa, and the pressure gradient is preset to increase by 6MPa per minute, so as to gradually increase the jetting pressure; 3. When the injection pressure reaches 35 MPa, the injection pressure is restored to normal parameters for reverse injection construction, and an inverted funnel 4 with a height of 1 m can be formed.
[0051] It should be noted that the above parameters can be designed according to actual needs and soil conditions. For example, when encountering a pebble layer with poor adhesion or relatively loose soil, the length of the inverted funnel 4 can be lengthened, the preset initial pressure is 5MPa, and the preset pressure gradient is increased by 3MPa per minute, so as to gradually increase the injection pressure. When the injection pressure reaches 35MPa, the injection pressure returns to normal parameters for back-spraying construction, and a 2m high inverted funnel 4 can be formed.
[0052] Preferably, the top of the inverted funnel is designed to be at a surface layer 3, and the bottom of the inverted funnel is designed to be at a second soil layer 2; And / or, the design elevation of the top of the inverted funnel is located at the first soil layer 1, and the design elevation of the bottom of the inverted funnel is located at the second soil layer 2.
[0053] Specifically, in order to prevent the inverted funnel 4 from falling into the liquefied soil layer, the top of the inverted funnel 4 needs to be embedded in the surface layer 3 or the first soil stratum 1 to give the inverted funnel 4 an upward pulling force. The third function of the surface layer 3 is to fix the inverted funnel 4. At the same time, it is necessary to avoid the collapse of the bottom surface of the surface layer 3 or the first soil stratum 1, so the bottom of the inverted funnel 4 needs to be lower than the bottom surfaces of the two, thereby playing an anti-collapse role.
[0054] Preferably, the diameter of the drill rod is 375 mm or 433 mm, the material of the drill rod is 27 silicon manganese steel or 40 molybdenum, and the wall thickness of the drill rod is not less than 25 mm.
[0055] Specifically, the pebble formation jet pile formation needs to adopt single nozzle jetting. When the reverse jetting method is used for construction, the lateral constraint is greatly weakened when jetting from top to bottom, and the reaction force of the nozzle will cause the nozzle and the drill rod to deviate. Compared with the diameter of the traditional rotary jet drill rod of 75mm, 90mm, 108mm, etc., the drill rod diameter in the scheme of the present invention is 375mm or 433mm, the material of the drill rod is 27 silicon manganese steel or 40 molybdenum, and the wall thickness of the drill rod is not less than 25mm, thereby improving the diameter, quality and rigidity of the drill rod, thereby further ensuring the verticality of the construction, thereby ensuring the quality of the pile formation.
[0056] Preferably, a method for treating a pebble layer is provided: In order to ensure that the slurry and pebbles are fully mixed, appropriate admixtures can be added to enhance the fluidity and adhesion of the slurry.
[0057] Furthermore, the admixture may be selected from anti-dispersion additives in water, bentonite, water glass, etc.
[0058] For a construction site with multiple strata, geological surveys show that 0-10 meters is a silty sand layer, 10-15 meters is a pebble layer, 15-20 meters is a silty fine sand layer, the pile top design elevation is -5m, and the pile bottom design elevation is -18m. Based on the above information, a specific construction plan is formulated: 1. For the surface layer above the design elevation of the pile top, that is, above -5m, the height of the inverted funnel 4 is designed to be 2m, and the top elevation of the inverted funnel can be obtained to be -3m; 2. No jetting is done in the area above -3m, only drilling is done. -3m to -5m is the area where the inverted funnel is located. Rotary jetting is started from -3m. The drilling speed of the drill is adjusted to 20cm / min. The initial pressure is 5MPa, and the jetting pressure is increased by 3MPa per minute, gradually increasing; 3. When the injection pressure reaches 35MPa, the injection pressure returns to normal parameters for reverse injection construction. At this time, a 2m high inverted funnel 4 can be formed to prevent the collapse of the upper soil, and the nozzle position is exactly at the designed elevation of the pile top (-5m); 4. Continue the jetting operation from top to bottom by reverse jetting until the pebble layer is encountered at -10m, and temporarily end the jetting operation; 5. According to the soil conditions of the pebble layer, the height of the inverted funnel 4 in the pebble layer is designed to be 1m, and the top elevation of the inverted funnel is -14m; 6. From -10m to -14m, do not jet grout but only drill down. Start jet grouting from -14m. Adjust the drilling speed of the drilling tool to 20cm / min. Take 5MPa as the initial pressure and increase the jet pressure by 6MPa per minute, gradually increasing the jet pressure. 7. When the injection pressure reaches 35MPa, the injection pressure is restored to normal parameters for reverse injection construction. At this time, an inverted funnel 4 with a height of 1m can be formed to prevent the collapse of the upper soil body, and the nozzle position is exactly at the boundary between the pebble layer and the lower fine sand layer (-15m); 8. Carry out backjetting in the fine sand layer with normal jetting parameters until the pile bottom design elevation reaches -18m, and then finish drilling; 9. Carry out jet grouting construction from -18m to -5m from bottom to top with normal construction parameters; 10. Pull the drill bit out of the hole to complete the pile construction.
[0059] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.
Claims
1. A liquid conversion rotary spraying method, characterized in that: It includes the following steps: Obtaining distribution information of soil strata, wherein the soil strata include a second soil stratum (2); Drilling is performed at a preset position on the surface by means of a drilling rig, and the drill rod of the drilling rig drives the sprinkler head to move vertically downward. When the sprinkler head is located at the second soil layer (2), the sprinkler head is turned on, otherwise, the sprinkler head is turned off, so that the second soil layer (2) forms a liquefied soil layer, until the sprinkler head reaches the designed elevation of the pile bottom; The sprinkler head is turned on, and the drill rod drives the sprinkler head to move vertically upward until the sprinkler head reaches the designed elevation of the pile top to form a jet jet pile.
2. The liquid conversion rotary spraying method according to claim 1, characterized in that: When the sprinkler is located at the second soil layer (2), the sprinkler is turned on, specifically including: According to the distribution information of the second soil stratum (2); If the second soil layer (2) has a layer; When the nozzle moves vertically downward and reaches a first threshold, the nozzle of the nozzle starts to spray, and the drill rod drives the nozzle to rotate until the nozzle moves vertically downward and reaches a second threshold.
3. The liquid conversion rotary spraying method according to claim 1, characterized in that: When the sprinkler is located at the second soil layer (2), the sprinkler is turned on, specifically including: According to the distribution information of the second soil stratum (2); If the second soil layer (2) has multiple layers; When the nozzle moves vertically downward and reaches the third threshold, the nozzle of the nozzle starts to spray, and the drill rod drives the nozzle to rotate until the nozzle moves vertically downward and reaches the fourth threshold; When the sprinkler head moves vertically downward and reaches the fifth threshold, the nozzle of the sprinkler head starts spraying, and the drill rod drives the nozzle to rotate until the sprinkler head moves vertically downward and reaches the sixth threshold; The above operation is repeated until all the second soil layers (2) form liquefied soil layers.
4. The liquid conversion rotary spraying method according to claim 1, characterized in that: The construction method also includes: The soil layer between the ground surface and the pile top design elevation is recorded as the surface layer (3); When the bottom of the ground surface layer (3) is the second soil stratum (2), an anti-collapse member is arranged between the ground surface layer (3) and the second soil stratum (2).
5. The liquid conversion rotary spraying method according to claim 1, characterized in that: The soil strata further include a first soil stratum (1); When the bottom of the first soil stratum (1) is the second soil stratum (2), an anti-collapse member is arranged between the first soil stratum (1) and the second soil stratum (2).
6. The liquid conversion rotary spraying method according to claim 4 or 5, characterized in that: The anti-collapse component is an inverted funnel (4).
7. The liquid conversion rotary spraying method according to claim 6, characterized in that: An inverted funnel (4) is provided, specifically comprising: When the drill rod of the drilling rig drives the sprinkler head to move vertically downward; When the sprinkler head reaches the designed elevation of the top of the inverted funnel, the nozzle of the sprinkler head starts to spray, and the drill rod drives the nozzle to rotate until the sprinkler head reaches the designed elevation of the bottom of the inverted funnel, forming an inverted funnel (4).
8. The liquid conversion rotary spraying method according to claim 7, characterized in that: The nozzle of the sprinkler starts to spray, and the drill rod drives the nozzle to rotate, including: The nozzle sprays at a preset initial pressure and a preset pressure gradient; When the spray pressure of the nozzle reaches the preset maximum pressure, the nozzle reaches the designed elevation of the bottom of the inverted funnel; The injection pressure of the nozzle becomes a pressure that causes the second soil layer (2) to form a liquefied soil layer.
9. The liquid conversion rotary spraying method according to claim 7, characterized in that: The top of the inverted funnel is designed to be located at the surface layer (3), and the bottom of the inverted funnel is designed to be located at the second soil layer (2); And / or, the design elevation of the top of the inverted funnel is located at the first soil stratum (1), and the design elevation of the bottom of the inverted funnel is located at the second soil stratum (2).
10. The liquid conversion rotary spraying method according to claim 1, characterized in that: The diameter of the drill rod is selected to be 375 mm or 433 mm, the material of the drill rod is selected to be 27 silicon manganese steel or 40 molybdenum, and the wall thickness of the drill rod is not less than 25 mm.