Construction method of supporting structure for foundation pit construction with ground-connected wall and guide wall

Abstract

The present invention relates to the field of engineering construction technology, and in particular to a construction method for a support structure for foundation pit construction of a ground-connected wall guide wall, including construction preparation, symmetrical casting of the guide wall; after the guide wall strength reaches the standard, wooden beams are set for support and mud is backfilled; slot sections are divided and slotting construction is carried out; during the slotting construction process, the slotting depth is measured, the slotting speed is calculated to judge the hardness of the formation, and different slotting methods are selected; the verticality of the slot wall is detected to judge the deviation of the slot section and the change range of the formation hardness; the specific position where the slot section has a deviation and the specific number of the slot sections where the deviation occurs are judged, the degree of deviation of the offset hole is judged according to the specific number, and the stamping parameters of the stamping equipment are adjusted; a steel cage is made and hoisted, the steel cage is lowered to cast concrete, and after the concrete pouring is completed, the conduit is disassembled to pull out the joint pipe. The present invention selects a slotting method according to the change of the formation hardness, and predicts and adjusts the collapse of the offset hole according to the verticality of the slot wall.

Description

Technical Field

[0001] The invention relates to the technical field of engineering construction, and in particular to a construction method of a supporting structure for foundation pit construction of a ground-connected wall and a guide wall. Background Art

[0002] The underground continuous wall is a foundation project that uses a trenching machine on the ground to dig a long and narrow deep trench along the peripheral axis of the deep excavation project under the condition of mud wall protection. After the trench is cleared, a steel cage is suspended in the trench, and then underwater concrete is poured using the conduit method to form a unit trench section. This process is carried out section by section to build a continuous reinforced concrete wall underground as a water interception, anti-seepage, load-bearing and water retaining structure.

[0003] Chinese Patent Publication No.: CN113202083A discloses a construction method for an underground continuous wall. After measuring and locating the construction site with a measuring instrument and obtaining the construction position of the underground continuous wall, the underground continuous wall is divided into multiple sections according to the construction position of the underground continuous wall and the construction drawings, and the corresponding construction slot sections are excavated to obtain slot holes, and a steel cage with a size corresponding to the current underground continuous wall section is made, and a limit plate is set on the steel cage, and the steel cage with the limit plate is placed in the slot hole, and then concrete is poured into the steel cage for pouring to obtain an underground continuous wall. By installing a limit plate at a certain distance outside the steel cage, the limit plate is used to limit the concrete during the subsequent pouring of the wall concrete, which prevents the underground continuous wall from intruding to a certain extent, avoids the chiseling of the intruding part of the wall during the later construction process, and reduces the economic cost and time cost of the construction; it can be seen that the construction method of the underground continuous wall has the following problems:

[0004] During the trenching construction process, the trench hole was skewed during the drilling construction of the lower bedrock, and the verticality of the trench wall was difficult to ensure, which affected the smooth lowering of the underground continuous wall steel cage. Summary of the invention

[0005] To this end, the present invention provides a construction method for a supporting structure for foundation pit construction of a ground-connected wall guide wall, so as to overcome the problem in the prior art that during the trenching construction process and the drilling construction of the lower bedrock, the trench hole is skewed, the verticality of the trench wall is difficult to ensure, and the smooth lowering of the underground continuous wall steel cage is affected.

[0006] To achieve the above object, the present invention provides a construction method of a supporting structure for foundation pit construction of a ground-connected wall and a guide wall, comprising:

[0007] Step S1, construction preparation and leveling of the site, preparation for guide wall construction, use of a total station to lay out before making the guide wall, appropriate placement of the guide wall, and symmetrical casting of the guide wall;

[0008] Step S2, preparing mud according to the proportion, setting wooden beams for support after the guide wall strength reaches the standard, and backfilling the mud;

[0009] Step S3, dividing the trench into sections according to the design requirements and the size of the trenching equipment, and performing trenching construction;

[0010] Step S4, during the trenching construction process, the trenching depth is measured in the initial detection period, the trenching speed in the initial detection period is calculated, the formation hardness is judged according to the change of the trenching speed, and different trenching methods are selected;

[0011] Step S5, detecting the verticality of the slot wall with the initial detection cycle, checking the deviation of the slot section and determining the change range of the formation hardness, and adjusting the initial detection cycle accordingly;

[0012] Step S6, calculating the verticality difference between the first section, the middle section, and the last section of the groove wall and the standard verticality, determining the specific position where the groove section has deviation and the specific number of groove sections where the deviation has occurred, determining the degree of deviation of the offset hole according to the specific number, and adjusting the stamping parameters of the stamping equipment;

[0013] Step S7, making and hoisting a steel cage, lowering the steel cage and pouring concrete, and after the concrete pouring is completed, removing the guide tube and pulling out the joint pipe;

[0014] The stamping parameters of the stamping equipment include the initial stamping stroke and the initial stamping frequency.

[0015] Further, the groove bottom depths at three positions in the middle and side ends of the groove section are measured in the initial detection cycle, and the average value of the three groove bottom depths is taken as the groove depth;

[0016] The grooving speed of the grooving construction in several initial detection cycles is calculated according to the grooving depth, and the grooving speed difference is calculated according to the actual grooving speed in any initial detection cycle and the historical grooving speed in the previous initial detection cycle.

[0017] If the grooving speed difference is less than the speed difference evaluation value, it is judged that the difference between the actual grooving speed and the historical grooving speed in the current initial detection period is within the normal range;

[0018] If the grooving speed difference is greater than or equal to the speed difference evaluation value, it is determined that the actual grooving speed in the current initial detection cycle is slow.

[0019] Furthermore, when the difference between the actual slotting speed in the current detection cycle and the historical slotting speed is within the normal range, the formation hardness in the current initial detection cycle is relatively small, and the slotting method continues to be the grab slotting;

[0020] When the actual grooving speed in the current detection cycle is slow and the formation hardness in the current initial detection cycle is large, the grooving method is changed to punching grooving.

[0021] Further, the verticality of the first section of the groove wall, the middle section of the groove wall and the last section of the groove wall of the groove section is detected in the initial detection cycle, and the average verticality of the three verticalities is calculated;

[0022] If the average verticality is within the standard verticality range, it is judged that there is no deviation in the slot section;

[0023] If the average verticality exceeds the standard verticality range, it is judged that the trench section has deviations and does not meet the verticality requirements of trench construction. The specific circumstances of the deviations in the trench section are detected;

[0024] The standard verticality interval is an interval consisting of the standard verticality and positive and negative error values.

[0025] Further, the process of detecting the specific situation of the deviation of the slot section includes:

[0026] If the slot section corresponding to the historical initial detection cycle deviates, it is judged that the soft soil layer is vibrated during the punching and slotting process, causing the soft soil layer deviation. The ratio of bentonite, water and soda ash in the mud preparation process is adjusted, or the frequency of removing soil residue at the bottom of the slot is increased.

[0027] If the slot section corresponding to the current initial detection cycle deviates, the change range of the formation hardness is determined.

[0028] Further, the process of determining the magnitude of the change in formation hardness includes:

[0029] Calculate the verticality difference between the average verticality and the standard verticality,

[0030] If the verticality difference is less than or equal to the verticality evaluation value, it is judged that the change range of the formation hardness is small;

[0031] If the verticality difference is greater than the verticality evaluation value, it is judged that the formation hardness changes greatly.

[0032] Furthermore, when the change in formation hardness is small, the boundary between the soft and hard formations is leveled, the initial detection period is reduced according to the ratio of the verticality difference to the verticality evaluation value, and the velocity difference evaluation value is reduced accordingly;

[0033] When the stratum hardness changes greatly, grouting reinforcement is performed on the boundary between soft and hard strata, and the initial detection cycle is reduced according to the ratio of the verticality evaluation value to the verticality difference, and the velocity difference evaluation value is reduced accordingly.

[0034] Furthermore, the first verticality difference, the second verticality difference and the third verticality difference between the first section, the middle section and the last section of the groove wall and the standard verticality are calculated.

[0035] If the first verticality difference is greater than the verticality evaluation value, it is judged that the first section of the groove wall has a deviation; if the second verticality difference is greater than the verticality evaluation value, it is judged that the middle section of the groove wall has a deviation; if the third verticality difference is greater than the verticality evaluation value, it is judged that the last section of the groove wall has a deviation.

[0036] Furthermore, if the number of segments that meet the judgment condition is less than three, it is judged that a biased hole occurs during the punching and slotting process, and the degree of biased hole deviation is relatively light;

[0037] If the number of segments that meet the judgment conditions is equal to three, it is judged that the degree of deviation of the offset hole is serious.

[0038] Furthermore, the offset hole is slightly offset, the offset hole is corrected, and the initial punching stroke of the punching device is reduced, and the initial punching frequency of the punching device is increased;

[0039] The deviation of the hole was serious and it was determined that the rock surface was inclined. The drilling was suspended and gravel was backfilled to the inclined area before drilling again.

[0040] Compared with the prior art, the beneficial effect of the present invention lies in that the trench section designed in the trenching construction process is deeper. If only a single test is performed on the trench section depth, the test result is inaccurate and easily causes large errors. The accuracy of trenching depth detection is increased by measuring the trench bottom depth at three positions of the middle and side ends of the trench section; as the trenching depth increases, the hardness of the stratum soil may increase or encounter sandstone strata. When the more common bucket trenching method encounters rock and soil, the trenching speed is greatly reduced or even unable to continue digging. The trench sections are divided from top to bottom according to the detection cycle, and the trenching speed is calculated according to the change of trenching depth within the detection cycle. The change of soil hardness in the stratum is judged by the speed of the trenching speed, the geological conditions and rock changes are grasped in advance, and the conversion cycle for converting to the trenching method is determined, thereby improving the efficiency of trenching construction, avoiding unnecessary wear on equipment, and the method of judging the hardness of the soil is more convenient.

[0041] Furthermore, during the trenching construction process, the trench section length and depth are relatively large. By measuring the verticality of the first, middle and last trench walls, the accuracy and uniformity of the trench wall verticality detection are improved to avoid large errors in the detection results. The trenching machine is used to level the junction of soft and hard strata to ensure uniform force during impact construction. When the hardness of the stratum soil at the junction of soft and hard strata changes greatly, the stratum near the junction is grouting reinforced in advance to prevent the occurrence of biased holes during construction. The detection cycle is adjusted according to the change in the hardness of the stratum soil. The speed difference evaluation value used to determine the trenching speed is negatively feedback adjusted with the change in the detection cycle, further improving the efficiency of trenching construction and the accuracy of judging the change in soil hardness.

[0042] Furthermore, during the trenching construction process, the hole collapse phenomenon mainly exists in the upper soft soil layer. The reason for the hole collapse is that the upper soft soil trench wall is repeatedly scoured and disturbed by the mud for a long time during the punching process, and the soil vibration caused by the drill bit impact causes the soft soil layer located in the upper trench section to collapse. The verticality of the upper and lower layers of the trench section is detected to predict the hole collapse of the soft soil layer, and the mud mix ratio is appropriately adjusted or admixtures are added according to the predicted trenching conditions. During the trenching process of the trench wall machine, the mud performance indicators are kept at a high density and viscosity in the trench section to avoid the collapse of the soft soil layer and reduce the efficiency of the trenching construction.

[0043] Furthermore, during the trenching construction process, during the drilling construction of the lower bedrock, the slot hole is skewed, and the verticality of the slot wall is difficult to ensure. According to the segmented detection of the verticality of the slot wall, the specific location of the deviated hole is further divided into the slot section, which is convenient for repairing and adjusting the deviated hole. When the degree of deviation of the deviated hole is relatively light, the hidden danger of the deviated hole is eliminated by adopting the method of slightly moving the pile driver and frequently hammering. If the degree of deviation is relatively heavy, it is judged that there is a tilt of the rock surface, so that the contact surface between the impact hammer and the rock layer cannot be evenly stressed. The drill bit is easily skewed during the drilling and punching process, which makes it difficult to correct the deviated hole. By using crushed stone backfill to re-punch the hole, the small stroke punching method is used to correct the deviated hole phenomenon in time, thereby reducing the influence of the deviated hole on the verticality of the slot wall during the trenching process. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a method flow chart of a construction method of a supporting structure for foundation pit construction of a ground-connected wall and guide wall in an embodiment of the present invention;

[0045] Figure 2 It is a schematic diagram of three-digging holes by digging a bucket to form a groove in an embodiment of the present invention;

[0046] Figure 3 It is a schematic diagram of the process of lowering a steel cage and pouring concrete in an embodiment of the present invention;

[0047] Figure 4 A flow chart of selecting a trenching method according to trenching speed to judge formation hardness in an embodiment of the present invention;

[0048] In the figure: 1- trough section, 2- guide wall, 3- steel cage, 4- joint pipe, 5- grab equipment. DETAILED DESCRIPTION

[0049] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0051] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0052] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] See also Figure 1-Figure 4 As shown, Figure 1 It is a method flow chart of a construction method of a supporting structure for foundation pit construction of a ground-connected wall and guide wall in an embodiment of the present invention; Figure 2 It is a schematic diagram of three-digging holes by digging a bucket to form a groove in an embodiment of the present invention; Figure 3 It is a schematic diagram of the process of lowering a steel cage and pouring concrete in an embodiment of the present invention; Figure 4 This is a flow chart of selecting a trenching method based on trenching speed to determine formation hardness in an embodiment of the present invention.

[0054] The present invention provides a construction method of a supporting structure for foundation pit construction of a ground-connected wall and a guide wall, comprising:

[0055] Step S1, construction preparation and leveling of the site, preparation for the construction of the guide wall 2, before making the guide wall 2, use a total station to lay out, appropriately place the guide wall 2, and symmetrically cast the guide wall 2;

[0056] Step S2, preparing mud according to the proportion, setting wooden beams for support after the guide wall 2 reaches the strength standard, and backfilling the mud;

[0057] Step S3, dividing the trench section 1 according to the design requirements and the size of the trenching equipment, and performing trenching construction;

[0058] Step S4, during the trenching construction process, the trenching depth is measured in the initial detection period, the trenching speed in the initial detection period is calculated, the formation hardness is judged according to the change of the trenching speed, and different trenching methods are selected;

[0059] Step S5, detecting the verticality of the slot wall with the initial detection cycle, checking the deviation of slot section 1 and determining the change range of the formation hardness, and adjusting the initial detection cycle accordingly;

[0060] Step S6, calculating the verticality difference between the first section, the middle section, and the last section of the slot wall and the standard verticality, determining the specific position where the slot segment 1 has a deviation and the specific number of the slot segments 1 having a deviation, determining the degree of deviation of the offset hole according to the specific number, and adjusting the stamping parameters of the stamping equipment;

[0061] Step S7, making and hoisting the steel cage 3, lowering the steel cage 3 to pour concrete, and after the concrete pouring is completed, removing the guide tube and pulling out the joint pipe 4;

[0062] The stamping parameters of the stamping equipment include the initial stamping stroke and the initial stamping frequency.

[0063] In this embodiment, the geological conditions of the ground-anchored wall construction site are soft upper strata and hard lower strata.

[0064] A trial trenching site is selected within the construction site, where the geological conditions are similar to those of the ground-anchored wall area.

[0065] The trenching construction is carried out by using a grab bucket device 5 for grab trenching. The grab bucket device 5 is a hydraulic grab bucket machine. The grab bucket trenching adopts the grab bucket device 5 to perform three-hole digging, first digging single holes at both ends of the trench section 1, and then digging the middle partition wall.

[0066] During the trenching construction process, a measuring hammer is used to measure the trench bottom depths at three locations in the middle and side ends of the trench section 1 in an initial detection cycle, and the average value of the three trench bottom depths is taken as the trenching depth;

[0067] The grooving speed of the grooving construction in several initial detection cycles is calculated according to the grooving depth, and the grooving speed difference is calculated according to the actual grooving speed in any initial detection cycle and the historical grooving speed in the previous initial detection cycle.

[0068] If the slotting speed difference is less than the speed difference evaluation value, it is judged that the difference between the actual slotting speed and the historical slotting speed in the current detection period is within the normal range, the formation hardness in the current initial detection period is small, and the slotting method continues to be grab slotting;

[0069] If the slotting speed difference is greater than or equal to the speed difference evaluation value, it is judged that the actual slotting speed in the current initial detection cycle is slow, the formation hardness in the current detection cycle is large, and the slotting method is changed to punching slotting;

[0070] When the grooving method is punching, a punching device is used to punch and groove with an initial punching stroke and an initial punching frequency, and the punching device is an impact drill.

[0071] The speed difference evaluation value is 20% of the average value of the sum of any actual grooving speed and the historical grooving speed in the previous detection cycle.

[0072] Specifically, the trench section 1 designed during the trenching construction process is relatively deep. If only a single test is performed on the trench section depth, the test result will be inaccurate and easily cause large errors. The accuracy of trenching depth detection is increased by measuring the trench bottom depth at three positions, the middle and the side ends of the trench section 1. As the trenching depth increases, the hardness of the stratum soil may increase or encounter sandstone strata. When the more common bucket trenching method encounters rock and soil, the trenching speed will be greatly reduced or even unable to continue digging. The trench section 1 is divided from top to bottom through the detection cycle, and the trenching speed is calculated according to the change in trenching depth within the detection cycle. The change in soil hardness in the stratum is judged by the speed of the trenching speed, the geological conditions and rock changes are grasped in advance, and the conversion cycle for switching to the trenching method is determined, thereby improving the efficiency of trenching construction and avoiding unnecessary wear on equipment. The method of judging the hardness of the soil is more convenient.

[0073] The verticality of the wall of the trench section 1 during the trenching construction process is detected in real time according to the initial detection cycle. The trench wall is scanned at the first section, middle section and last section of the trench section 1 using an ultrasonic wall measuring instrument to detect the verticality of the first section, middle section and last section of the trench wall of the trench section 1, and the average verticality of the three verticalities is calculated;

[0074] If the average verticality is within the standard verticality range, it is determined that slot section 1 has no deviation;

[0075] If the average verticality exceeds the standard verticality range, it is determined that the slot section 1 has a deviation and does not meet the verticality requirement of the trench construction, and the specific situation of the deviation of the slot section 1 is detected;

[0076] If the slot section 1 corresponding to the historical initial detection cycle deviates, it is judged that the soft soil layer is vibrated during the punching and grooving process, causing the soft soil layer deviation.

[0077] Adjust the ratio of bentonite, water and soda ash in the mud preparation process to reduce the impact of mud scouring on the soft soil tank wall, or increase the frequency of removing soil residues at the bottom of the tank to reduce the soil vibration caused by the drill bit impacting the bottom of the tank during punching;

[0078] If there is a deviation in the slot section 1 corresponding to the current initial detection cycle, the verticality difference between the average verticality and the standard verticality is calculated to determine the change range of the formation hardness.

[0079] If the verticality difference is less than or equal to the verticality evaluation value, it is judged that the change range of the formation hardness is small, and the groove forming machine is used to level the junction of the soft and hard formations, and the initial detection cycle is reduced according to the ratio of the verticality difference to the verticality evaluation value, and the velocity difference evaluation value is reduced accordingly;

[0080] If the verticality difference is greater than the verticality evaluation value, it is judged that the change in stratum hardness is large, and grouting reinforcement is performed on the boundary between soft and hard strata. The initial detection cycle is reduced according to the ratio of the verticality evaluation value to the verticality difference, and the velocity difference evaluation value is reduced accordingly.

[0081] The standard verticality interval is an interval consisting of the standard verticality and positive and negative error values. The verticality error is generally controlled within 3%, and the verticality evaluation value is 5% of the standard verticality.

[0082] Specifically, during the trenching construction process, the trench section length and depth are relatively large. By measuring the verticality of the first, middle and last trench walls, the accuracy and uniformity of the trench wall verticality detection are improved to avoid large errors in the detection results. A trenching machine is used to level the junction of soft and hard strata so that the force is evenly distributed during impact construction. When the hardness of the stratum at the junction of soft and hard strata changes greatly, grouting reinforcement is performed in advance on the stratum near the junction to prevent the occurrence of skewed holes during construction. The detection cycle is adjusted according to the change in the hardness of the stratum soil. The speed difference evaluation value used to determine the trenching speed is negatively feedback-adjusted with the change in the detection cycle, further improving the efficiency of trenching construction and the accuracy of judging the change in soil hardness.

[0083] During the trenching construction process, the hole collapse phenomenon mainly exists in the upper soft soil layer. The reason for the hole collapse is that the upper soft soil trench wall is repeatedly scoured and disturbed by the mud for a long time during the punching process, and the soil vibration caused by the drill bit impact causes the soft soil layer located in the upper trench section to collapse. The verticality of the upper and lower layers of the trench section 1 is detected to predict the hole collapse of the soft soil layer, and the mud mix ratio is appropriately adjusted or admixtures are added according to the predicted trenching conditions. During the trenching process of the trench wall machine, the mud performance indicators are kept at a high density and viscosity in the trench section 1 to avoid the collapse of the soft soil layer and reduce the efficiency of the trenching construction.

[0084] Calculate the verticality difference between the first section, the middle section, and the last section of the slot wall and the standard verticality, and determine the specific location where the slot section 1 has a deviation and the specific number of slot sections 1 that have a deviation;

[0085] Divide slot section 1 from left to right into the first section, the middle section, and the last section, and calculate the first verticality difference, the second verticality difference, and the third verticality difference between the first section, the middle section, and the last section and the standard verticality.

[0086] If the first verticality difference is greater than the verticality evaluation value, it is judged that the first section of the groove wall has a deviation; if the second verticality difference is greater than the verticality evaluation value, it is judged that the middle section of the groove wall has a deviation; if the third verticality difference is greater than the verticality evaluation value, it is judged that the last section of the groove wall has a deviation; and a deviated hole occurs during the punching and grooving process.

[0087] in,

[0088] If the number of segments that meet the judgment condition is less than three, it is judged that the deviation of the offset hole is relatively light, and the offset hole is corrected, and the initial punching stroke of the punching device is reduced, and the initial punching frequency of the punching device is increased;

[0089] If the number of sections that meet the judgment conditions is equal to three, it is judged that the deviation degree of the deviation hole is serious and the rock surface of the formation is inclined. The punching is suspended and gravel is backfilled to the inclined area, and then the punching is restarted.

[0090] In this embodiment, when it is determined that a deviated hole occurs during the punching and grooving process, the punching is suspended to determine the degree of deviation of the deviated hole. When the deviated hole cannot be corrected, gravel is backfilled to 2m above the deviated part, and the punching construction is restarted, and a small stroke of less than 0.5m is used to punch the hole, and the stroke is gradually increased after it returns to normal.

[0091] During punching construction, follow the principle of deep main hole and shallow auxiliary hole to carry out cyclic punching construction. Do not punch to the bottom all the way. The main hole should be no less than 0.5m deeper than the auxiliary hole to ensure the free surface when the punch drill bit hits the hole. When the problem of offset hole occurs, stop punching in time and use the pile driver to move slightly and hammer frequently.

[0092] Specifically, during the trenching construction process, during the drilling construction of the lower bedrock, the slot hole is skewed, and the verticality of the slot wall is difficult to ensure. According to the segmented detection of the verticality of the slot wall, the specific position of the deviated hole in slot section 1 is further divided to facilitate the repair and adjustment of the deviated hole. When the degree of deviation of the deviated hole is relatively light, the hidden danger of the deviated hole is eliminated by adopting the method of slightly moving the pile driver and frequently hammering. If the degree of deviation is severe, it is judged that there is a tilt of the rock surface, so that the contact surface between the impact hammer and the rock layer cannot be evenly stressed. The drill bit is easily skewed during the drilling and punching process, which makes it difficult to correct the deviated hole. By using crushed stone backfill and re-punching construction, the deviated hole phenomenon is corrected in time by using small stroke punching, thereby reducing the influence of the deviated hole on the verticality of the slot wall during the trenching process.

[0093] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A construction method for a supporting structure for foundation pit construction of a ground-connected wall and a guide wall, characterized in that: include: Step S1, construction preparation and leveling of the site, preparation for guide wall construction, use of a total station to lay out before making the guide wall, appropriate placement of the guide wall, and symmetrical casting of the guide wall; Step S2, preparing mud according to the proportion, setting wooden beams for support after the guide wall strength reaches the standard, and backfilling the mud; Step S3, dividing the trench into sections according to the design requirements and the size of the trenching equipment, and performing trenching construction; Step S4, during the trenching construction process, the trenching depth is measured in the initial detection period, the trenching speed in the initial detection period is calculated, the formation hardness is judged according to the change of the trenching speed, and different trenching methods are selected; Step S5, detecting the verticality of the slot wall with the initial detection cycle, checking the deviation of the slot section and determining the change range of the formation hardness, and adjusting the initial detection cycle accordingly; The process of detecting the specific situation of the deviation of the slot section includes: If the slot section corresponding to the historical initial detection cycle deviates, it is judged that the soft soil layer is vibrated during the punching and slotting process, causing the soft soil layer deviation. The ratio of bentonite, water and soda ash in the mud preparation process is adjusted, or the frequency of removing soil residue at the bottom of the slot is increased. If the slot section corresponding to the current initial detection cycle deviates, the magnitude of the change in formation hardness is determined; The process of determining the magnitude of changes in formation hardness include, Calculate the verticality difference between the average verticality and the standard verticality, If the verticality difference is less than or equal to the verticality evaluation value, it is judged that the change range of the formation hardness is small; If the verticality difference is greater than the verticality evaluation value, it is judged that the formation hardness changes greatly; When the change in formation hardness is small, the boundary between the soft and hard formations is leveled, the initial detection cycle is reduced according to the ratio of the verticality difference to the verticality evaluation value, and the velocity difference evaluation value is reduced accordingly; When the change in stratum hardness is large, grouting reinforcement is performed on the boundary between soft and hard strata, and the initial detection cycle is reduced according to the ratio of the verticality evaluation value to the verticality difference value, and the velocity difference evaluation value is reduced accordingly; The speed difference evaluation value is used to compare with the slotting speed difference value, which is calculated based on the actual slotting speed in any initial detection cycle and the historical slotting speed in the previous initial detection cycle; Step S6, calculating the verticality difference between the first section, the middle section, and the last section of the groove wall and the standard verticality, determining the specific position where the groove section has deviation and the specific number of groove sections where the deviation has occurred, determining the degree of deviation of the offset hole according to the specific number, and adjusting the stamping parameters of the stamping equipment; Step S7, making and hoisting a steel cage, lowering the steel cage and pouring concrete, and after the concrete pouring is completed, removing the guide tube and pulling out the joint pipe; The stamping parameters of the stamping equipment include the initial stamping stroke and the initial stamping frequency.

2. The construction method of the supporting structure for foundation pit construction of the ground-connected wall guide wall according to claim 1 is characterized in that: The groove bottom depths at three locations in the middle and side ends of the groove section are measured during the initial detection cycle, and the average value of the three groove bottom depths is taken as the groove depth; The grooving speed of the grooving construction in several initial detection cycles is calculated according to the grooving depth, and the grooving speed difference is calculated according to the actual grooving speed in any initial detection cycle and the historical grooving speed in the previous initial detection cycle. If the grooving speed difference is less than the speed difference evaluation value, it is judged that the difference between the actual grooving speed and the historical grooving speed in the current initial detection period is within the normal range; If the grooving speed difference is greater than or equal to the speed difference evaluation value, it is determined that the actual grooving speed in the current initial detection cycle is slow.

3. The construction method of the supporting structure for foundation pit construction of the ground-connected wall guide wall according to claim 2 is characterized in that: When the difference between the actual trenching speed and the historical trenching speed in the current initial detection cycle is within the normal range, the formation hardness in the current initial detection cycle is relatively small, and the trenching method continues to be the grab trenching; When the actual grooving speed in the current initial detection cycle is slow, the formation hardness in the current initial detection cycle is relatively large, and the grooving method is changed to punching grooving.

4. The construction method of the supporting structure for foundation pit construction of the ground-connected wall guide wall according to claim 1 is characterized in that: The verticality of the first section, the middle section and the last section of the groove wall of the groove section is detected in the initial detection cycle, and the average verticality of the verticality of the first section, the middle section and the last section of the groove wall is calculated; If the average verticality is within the standard verticality range, it is judged that there is no deviation in the slot section; If the average verticality exceeds the standard verticality range, it is judged that the trench section has deviations and does not meet the verticality requirements of trench construction. The specific circumstances of the deviations in the trench section are detected; The standard verticality interval is an interval consisting of the standard verticality and positive and negative error values.

5. The construction method of the supporting structure for foundation pit construction of the ground-connected wall guide wall according to claim 1, characterized in that: Calculate the first verticality difference, second verticality difference and third verticality difference between the first section, middle section and last section of the groove wall and the standard verticality. If the first verticality difference is greater than the verticality evaluation value, it is judged that the first section of the groove wall has a deviation; if the second verticality difference is greater than the verticality evaluation value, it is judged that the middle section of the groove wall has a deviation; if the third verticality difference is greater than the verticality evaluation value, it is judged that the last section of the groove wall has a deviation.

6. The construction method of the supporting structure for foundation pit construction of the ground-connected wall guide wall according to claim 5, characterized in that: If the number of slot wall segments that meet the judgment condition of slot wall deviation is less than three, it is judged that a deviation hole occurs during the punching process, and the deviation degree of the deviation hole is relatively light; If the number of slot wall segments that meet the criteria for slot wall deviation is equal to three, it is judged that the degree of deviation of the offset hole is severe.

7. The construction method of the supporting structure for foundation pit construction of the ground-connected wall guide wall according to claim 6 is characterized in that: When the deviation of the offset hole is slight, the offset hole is corrected, the initial punching stroke of the punching equipment is reduced, and the initial punching frequency of the punching equipment is increased; When the deviation of the hole is serious, it is determined that the rock surface is inclined, and the drilling is suspended, gravel is backfilled to the inclined area, and then the drilling is resumed.

Images