Foundation pit supporting system

Abstract

The utility model discloses two foundation pit supporting systems, the first foundation pit supporting system comprises a top beam and a steel pile, when the steel pile sinks, a static pressure pile machine is detachably installed on the top beam, the steel pile is detachably connected to the top beam, and the steel pile sinking later sinks underground with the steel pile sinking first as a counter-force mechanism; the second type comprises a top beam, a cast-in-place pile and a steel pile, wherein the cast-in-place pile is connected to the top beam; when the steel pile sinks, the static pressure pile machine is detachably mounted on the top beam, and the steel pile sinks underground by taking the cast-in-place pile as a counter-force mechanism; or the steel pile which sinks later sinks to the underground by taking the cast-in-place pile and the steel pile which sinks firstly as a counter-force mechanism together. The steel pile sinking in advance can serve as a counter-force mechanism, or the steel pile sinking in advance and the cast-in-place pile jointly serve as the counter-force mechanism to continue to sink the steel pile, and construction of other counter-force mechanisms on the ground is avoided.

Description

Technical Field

[0001] The utility model relates to a foundation pit supporting system. Background Art

[0002] In foundation pit support systems, steel piles are widely used due to their recyclable advantages. During the construction of support systems, static pile driving has low noise and can be constructed in densely populated areas, so it is widely used in foundation pit construction in cities. When static pile driving is used, it is necessary to set up reaction measures such as anchor rods or counterweights on the ground. When anchor rods are used as reaction measures, a large number of anchor rods need to be equipped and pre-buried in the ground. When counterweights are used as reaction measures, the counterweights need to be transferred from the completed pile driving construction point to the next pile driving construction point, resulting in the need to frequently transfer the counterweights, which makes the construction efficiency of static pile driving low. Utility Model Content

[0003] In order to solve the problem of low construction efficiency caused by frequent transfer of counterweight when sinking pile body by static pile pressure method in the prior art, the utility model first proposes a foundation pit support system, which includes a crown beam and a steel pile, a through-beam hole is reserved on the crown beam and a connecting piece is embedded in the crown beam, the steel pile is sunk into the ground through the through-beam hole, an anti-pullout hole is opened on the steel pile, and the anti-pullout rod can be inserted into the anti-pullout hole and is located on the upper side of the crown beam; when sinking the steel pile, the static pile pressure machine is detachably installed on the crown beam through the connecting piece, and the anti-pullout rod is pressed on the upper surface of the crown beam, so that the steel pile that sinks later can sink into the ground with the steel pile that sinks first as a reaction mechanism. The crown beam adopts reinforced concrete structure or steel structure. Specifically, the steel pile is a steel pipe pile and / or H steel pile. That is, in the same embodiment, the steel piles can all adopt steel pipe piles or H steel piles, or can partially adopt steel pipe piles and partially adopt H steel piles.

[0004] The anti-pullout rod can be made of solid rod, hollow rod and various types of steel. Preferably, the anti-pullout rod is a rod with a square or rectangular cross section, so that the anti-pullout rod has a larger contact area with the crown beam, and preferably the inner circumference of the anti-pullout hole is the same shape as the outer circumference of the anti-pullout rod, so that the anti-pullout rod has a larger contact area with the anti-pullout hole.

[0005] The above foundation pit support system adopts the following construction method during construction, and the specific steps are as follows:

[0006] (1.1) The following two methods are used to construct the crown beam:

[0007] Method 1: construct the crown beam and reserve a through-beam hole on the crown beam, the through-beam hole passing through the upper and lower surfaces of the crown beam; sink part of the steel piles into the ground through the through-beam hole, insert the anti-pullout rod into the anti-pullout hole of the sunken steel pile, and make the anti-pullout rod tightly press against the upper surface of the crown beam;

[0008] Method 2: First, sink some steel piles into the ground, then construct the crown beam, and reserve a through-beam hole on the crown beam, which passes through the upper and lower surfaces of the crown beam; insert the anti-pullout rod into the anti-pullout hole of the sunken steel pile, and make the anti-pullout rod tightly press against the upper surface of the crown beam;

[0009] (1.2) Install a static pile driver on the crown beam and position the static pile driver on the upper side of the beam hole adjacent to the steel pile that has been sunk. Use the static pile driver to sink the steel pile into the ground through the beam hole. When sinking the steel pile, the steel pile that has been sunk is connected to the crown beam via an anti-pullout rod. The steel pile that has been sunk is used as a reaction mechanism to sink the steel pile into the ground.

[0010] (1.3) Repeat step (1.2) until all the steel piles made of steel sections are sunk.

[0011] During the construction of the above foundation pit support system, the construction of the crown beam is first completed and the existing technology is used to complete the sinking of some steel piles. The crown beam is used to connect the steel piles that have been sunk to the static pile driver, and the steel piles that have been sunk are used as the reaction force mechanism of the steel piles that are sunk later, thereby avoiding the construction of new reaction mechanisms such as anchor rods on the ground to improve construction efficiency. Since the construction of new reaction mechanisms is avoided, the construction cost can also be reduced. During the construction process of the support system in this application, it is necessary to use existing mature technology to sink a certain number of steel piles into the ground through the beam holes, or after a certain number of steel piles are sunk, the construction of the crown beam is carried out, and then the sunken steel piles are used as the reaction force mechanism. Generally, only two steel piles are needed to meet the reaction force required for sinking steel piles. Therefore, although some steel piles need to be sunk first before the present application can be formally used to sink the steel piles, compared with the sinking construction of hundreds, thousands, or even tens of thousands of steel piles in the whole process, it can still greatly improve the construction efficiency and reduce the construction cost.

[0012] In the prior art, even if the above-mentioned anchor rod is not used as the reaction force mechanism, it is also necessary to equip the corresponding counterweight or use a pile driver with a large deadweight for construction. Whether using a counterweight or a pile driver with a large deadweight for construction, there are problems such as low pile driver movement efficiency and high construction costs.

[0013] At present, the crown beam is constructed after all the steel piles are sunk. In this application, the crown beam is constructed in advance, and the steel piles that have been sunk are connected to the static pile driver by means of the crown beam, and the steel piles that have been sunk are used as the reaction force mechanism for the subsequent sinking steel piles, thereby avoiding the need to set up new reaction force mechanisms such as anchor rods or counterweights on the ground.

[0014] In the present application, when all the steel piles are sunk by a static pile driver, only the first several steel piles that are sunk need to be sunk by anchor rods or counterweights. When the reaction force provided by the already sunk steel piles can meet the reaction force required for the subsequent steel piles to sink, the subsequent steel piles do not need anchor rods or counterweights, thereby improving the construction efficiency. Since there is no need to set reaction mechanisms such as anchor rods or counterweights for the sinking of each steel pile, the construction cost can also be reduced. During the construction of the foundation pit support system in the present application, it is necessary to first complete the construction of the crown beam, and then use the existing mature technology to sink a certain number of steel piles into the ground through the beam holes, and then use the already sunk steel piles as a reaction mechanism to continue sinking the steel piles; or after a certain number of steel piles have been sunk, the crown beam is constructed, and then the already sunk steel piles are used as a reaction mechanism to continue sinking the steel piles. In some areas, only one or two steel piles are needed to meet the reaction force required for the subsequent sinking of the steel piles. Therefore, although some steel piles need to be sunk first before the present application can be formally used to sink the steel piles, compared with the sinking construction of hundreds, thousands, or even tens of thousands of steel piles in the whole process, it can still greatly improve construction efficiency and reduce construction costs.

[0015] Secondly, the present application also proposes a second foundation pit support system, which includes a crown beam, cast-in-place piles and steel piles. The crown beam is connected to the cast-in-place piles, and a through-beam hole is reserved on the crown beam and a connecting piece is pre-embedded. The steel pile is sunk into the ground through the through-beam hole; when the steel pile is sunk, the static pile driver is detachably mounted on the crown beam via the connecting piece, and the cast-in-place pile is used as a reaction mechanism to sink the steel pile into the ground; or an anti-pull-out hole is opened on the steel pile, and the anti-pull-out rod can be inserted into the anti-pull-out hole and is located on the upper side of the crown beam. When the steel pile is sunk, the static pile driver is detachably mounted on the crown beam via the connecting piece, and the anti-pull-out rod is tightly pressed against the upper surface of the crown beam. The steel pile that sinks later can sink into the ground with the cast-in-place pile and the steel pile that sinks earlier acting as a reaction mechanism.

[0016] The second construction method of the foundation pit support system includes the following steps:

[0017] (2.1) Construction of the crown beam: construct the cast-in-place piles, and then construct the crown beam, so that the crown beam is connected to the cast-in-place piles, and a through-beam hole is reserved on the crown beam and a connecting piece is embedded in advance. The through-beam hole passes through the upper surface and the lower surface of the crown beam;

[0018] (2.2) Install the static pile driver on the crown beam and make it located on the upper side of the beam hole. Use the cast-in-place pile as the reaction mechanism and use the static pile driver to sink the steel pile through the beam hole into the ground. The steel pile is made of steel section.

[0019] (2.3) Connect the sunken steel piles to the crown beam, use the cast-in-place piles and the sunken steel piles as a reaction mechanism, and use a static pile driver to continue sinking the steel piles.

[0020] When in some areas, due to the small lateral friction between the steel piles and the underground soil, a large number of steel piles are needed to meet the reaction force required for the subsequent sinking of the steel piles, the large reaction force provided by the cast-in-place piles can effectively guarantee the reaction force required for the sinking of the steel piles. At this time, a single cast-in-place pile can meet the reaction force required for the sinking of the steel piles.

[0021] When in certain construction areas, due to the small lateral friction between the steel piles and the underground soil, a large number of steel piles are needed to meet the reaction force required for the subsequent sinking of the steel piles. The large reaction force provided by the cast-in-place piles can effectively guarantee the reaction force required for sinking the steel piles, thereby overcoming the problem of small lateral friction between the steel piles and the underground soil.

[0022] In addition, since the cast-in-place piles cannot be recovered and always remain underground, they can still resist the pressure of the soil outside the foundation pit after the steel piles are pulled out and recovered. After the construction of the underground structure is completed, the gap between the underground structure and the edge of the foundation pit needs to be backfilled. Although the backfill soil is compacted during the backfilling process, the backfill soil will still collapse to a certain extent over time, causing the ground to collapse and causing the soil outside the original foundation pit to collapse toward the foundation pit. Therefore, when the backfill soil collapses, the collapse range of the ground will exceed the edge of the original foundation pit, causing greater danger, especially in areas with softer soil. Using this solution, cast-in-place piles can be arranged in areas with softer soil. After the steel piles are recovered, the cast-in-place piles can still be used as support piles to reduce or even avoid the collapse of the soil outside the original foundation pit caused by the collapse of the backfill soil, reducing the danger caused by the collapse of the backfill soil. Of course, according to actual needs, several cast-in-place piles can be set at the edge of the foundation pit to replace some steel piles.

[0023] Furthermore, in order to avoid the upward movement of the sunken steel piles that serve as a reaction force mechanism during the sinking process, which would affect their stability underground, when the anti-pullout rods are inserted into the anti-pullout holes, the anti-pullout rods are tightly pressed against the upper surface of the crown beam.

[0024] Furthermore, in order to prevent the anti-pullout rod from causing local damage to the crown beam and affecting the overall quality of the crown beam, a steel pad is laid on the upper surface of the crown beam, and the anti-pullout rod is tightly pressed against the steel pad. In the process of using the steel pile as a reaction mechanism, the anti-pullout rod will exert a huge pressure on the crown beam. Since the crown beam adopts a reinforced concrete structure, it will produce a shearing effect on the crown beam. The tensile strength of concrete is relatively weak. Under the strong squeezing of the anti-pullout rod, it is very likely to cause cracks in the crown beam, or even cause it to break. The steel pad is used to increase the contact area between the anti-pullout rod and the crown beam to avoid damage to the crown beam.

[0025] Furthermore, in order to prevent the anti-pullout hole from being deformed under the squeezing of the anti-pullout rod, which would affect the secondary use of the steel pile, a reinforcement piece is fixed to the upper end of the steel pile. The reinforcement piece is located on the upper side of the anti-pullout hole, and the anti-pullout rod tightly presses the reinforcement piece on it. The reinforcement piece is used to improve the overall strength of the upper end of the steel pile, reduce or eliminate the deformation of the anti-pullout hole, and ensure the secondary use of the steel pile.

[0026] Specifically, in order to ensure the connection strength, the connection piece is a precision-rolled threaded steel bar, and the precision-rolled threaded steel bar extends upward from the upper surface of the crown beam.

[0027] Furthermore, the through-beam hole has an inner circumference with the same shape as the outer circumference of the steel pile. This design enables the steel pile to fit closely to the through-beam hole. When selecting the pull-out rod, only the shear strength of the pull-out rod needs to be considered. To avoid an excessively large gap between the steel pile and the inner wall of the through-beam hole, the bending strength of the pull-out rod also needs to be considered. This design also enables the through-beam hole to function as a guide hole.

[0028] Specifically, when the soil in the construction area is relatively hard, one and only one cast-in-place pile is provided.

[0029] Specifically, at least two cast-in-place piles are provided, and there are 0-20 steel piles between two adjacent cast-in-place piles. Since the cast-in-place piles cannot be recovered and are always kept underground, they can still play the role of resisting the pressure of the soil outside the foundation pit after the steel piles are pulled out and recovered. After the construction of the underground structure is completed, the gap between the underground structure and the edge of the foundation pit needs to be backfilled. Although the backfill soil is compacted during the backfilling process, the backfill soil will still collapse to a certain extent over time, causing the collapse of the ground and causing the soil outside the original foundation pit to collapse toward the foundation pit. Therefore, when the backfill soil collapses, the collapse range of the ground will exceed the edge of the original foundation pit, causing greater danger, especially in areas with softer soil. With this design, the cast-in-place piles can be arranged in areas with softer soil. After the steel piles are recovered, the cast-in-place piles can still be used as support piles, reducing or even avoiding the collapse of the soil outside the original foundation pit caused by the collapse of the backfill soil, and reducing the danger caused by the collapse of the backfill soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is the first structural schematic diagram of the foundation pit support system.

[0031] Figure 2 It is a structural diagram of steel piles.

[0032] Figure 3 It is the second structural schematic diagram of the foundation pit support system.

[0033] Figure 4 It is a structural diagram of H steel pile.

[0034] Figure 5 yes Figure 4 Top view of the .

[0035] Figure 6 yes Figure 1 The construction flow chart of the foundation pit support system is shown.

[0036] Figure 7 This is the state diagram when the third steel pipe pile is sinking.

[0037] Figure 8 This is a state diagram of the static pile driver when it is working.

[0038] Fig. 9 It is the third structural schematic diagram of the foundation pit support system.

[0039] Fig.10 yes Fig. 9 The construction flow chart of the foundation pit support system is shown. DETAILED DESCRIPTION

[0040] Example 1

[0041] The foundation pit support system in this application is described below.

[0042] See also Figure 1 and Figure 2 The foundation pit support system includes a crown beam 10 and a steel pile 20. Figure 1 Only five steel piles 20 are shown as examples. In this embodiment, the steel piles are all made of steel pipes, which are called steel pipe piles. For the convenience of description, the five steel pipe piles are sequentially called the first steel pipe pile 21, the second steel pipe pile 22, the third steel pipe pile 23, the fourth steel pipe pile 24 and the fifth steel pipe pile 25.

[0043] Please also see Figure 6 In step (a), a through-beam hole is reserved on the crown beam, and each steel pipe pile has a through-beam hole. In the order of the first steel pipe pile 21 to the fifth steel pipe pile 25, the five through-beam holes corresponding to the five steel pipe piles are the first through-beam hole 121, the second through-beam hole 122, the third through-beam hole 123, the fourth through-beam hole 124 and the fifth through-beam hole 125. Each steel pipe pile is sunk into the ground through the corresponding through-beam hole. In this embodiment, each through-beam hole is circular, that is, the through-beam hole has an inner circumference that is the same as the outer circumference of the steel pipe pile. In this embodiment, the crown beam adopts a reinforced concrete structure. It can be understood that in another embodiment, the crown beam can also adopt a steel structure.

[0044] Two anti-pullout hole groups are provided on each steel pipe pile, and each anti-pullout hole group includes two anti-pullout holes 202 arranged along a horizontal straight line. The two horizontal straight lines where the anti-pullout holes 202 in the two anti-pullout hole groups are located are arranged in parallel and at the same height. Each anti-pullout hole group corresponds to an anti-pullout rod 32, and each anti-pullout rod 32 is sequentially inserted into the two anti-pullout holes 202 in the corresponding anti-pullout hole group, and the anti-pullout rod is tightly pressed against the upper surface of the crown beam. The anti-pullout holes all penetrate the wall of the steel pipe pile. In the pile of this embodiment, the anti-pullout rod adopts a solid square rod, and the inner circumference of the anti-pullout hole is the same shape as the outer circumference of the anti-pullout rod.

[0045] It can be understood that in another embodiment, the heights of the two horizontal straight lines where the anti-pulling holes 202 in the two anti-pulling hole groups are located can also be different. In this case, pads need to be placed on the crown beam to support the anti-pulling rods at a higher position. Of course, in yet another embodiment, the two horizontal straight lines where the anti-pulling holes 202 in the two anti-pulling hole groups are located can also be intersected, but the intersection point needs to be located outside the steel pipe pile to avoid interference between the two anti-pulling rods. Of course, the heights of the two horizontal straight lines can also be different and non-parallel. In this case, the two anti-pulling rods can be staggered from each other in the height direction. When observed in the vertical direction, the two anti-pulling rods intersect or the extension lines of the two anti-pulling rods intersect. In addition, only one anti-pulling hole group or more than two anti-pulling hole groups can be set. It can be understood that in other embodiments, only one anti-pull-out hole in the form of a through hole or only one blind hole with an opening facing outward can be set on the pipe wall of the steel pipe pile. Since this method cannot guarantee that the anti-pull-out rod can be stably pressed against the crown beam during subsequent construction, this method of opening the anti-pull-out hole is generally not recommended, although this method can be used under certain conditions.

[0046] See also Figure 8 The steel pipe pile is sunk by a static pile driver 300. In order to enable the static pile driver 300 to be stably connected to the crown beam 10, a connecting piece 11 is embedded in the crown beam. The connecting piece specifically adopts fine-rolled threaded steel bars. The connecting piece corresponds one by one to the mounting holes on the bottom plate 310 of the static pile driver 300. When sinking the steel pipe pile, the mounting holes on the bottom plate of the static pile driver are passed through the corresponding fine-rolled threaded steel bars, and then the nuts are screwed on the fine-rolled threaded steel bars, so that the static pile driver can be detachably mounted on the crown beam. The static pile driver is also called a static pile driver. The static pile driver adopts existing mature equipment, such as the static pile driver with patent number CN2020203306274 and the name of anchor static pile driver. Of course, other similar static pile drivers can also be used. When sinking the steel pipe piles, the crown beam and the anti-pullout rod press against each other, and the steel pipe piles that have completed sinking are hooked on the crown beam through the anti-pullout rod, so that the steel pipe piles that sink later use the steel pipe piles that sink earlier as a reaction mechanism to sink into the ground.

[0047] In this embodiment, in order to avoid partial damage to the crown beam due to excessive pressure during the sinking of the steel pipe pile, thereby affecting the overall strength of the crown beam, a steel pad 31 is laid on the upper surface of the crown beam, and the anti-pull rod 32 is supported on the steel pad 31, so that the anti-pull rod is indirectly and tightly pressed against the upper surface of the crown beam through the steel pad. In order to avoid large deformation of the anti-pull hole 202 under the squeezing of the anti-pull rod during the sinking of the steel pipe pile, a steel ring 201 is welded on the inner wall of the upper end of the steel pipe pile. The steel ring 201 serves as a reinforcement, and the lower surface of the steel ring is at the same height as the uppermost end of the anti-pull hole, so that when the steel pipe pile is sunk, the anti-pull rod can press against the lower surface of the steel ring and the inner wall of the anti-pull hole at the same time.

[0048] It is understood that in other embodiments, a steel ring may be welded on the inner wall of the steel pipe pile or on the inner and outer walls of the steel pipe pile. Of course, arc-shaped steel plates may be used to replace the steel ring while ensuring strength.

[0049] The construction method of the foundation pit support system in this embodiment is described below. The steps of the construction method are as follows:

[0050] (1.1) Please refer to Figure 6 In step (a), a crown beam 10 is constructed, and a beam-through hole is reserved on the crown beam 10, the beam-through hole passing through the upper surface and the lower surface of the crown beam, Figure 6 Only five beam-penetrating holes are shown in the figure for example. For the convenience of description, the five beam-penetrating holes are sequentially referred to as the first beam-penetrating hole 121, the second beam-penetrating hole 122, the third beam-penetrating hole 123, the fourth beam-penetrating hole 124 and the fifth beam-penetrating hole 125. Pre-embedded fine-rolled threaded steel bars are used as the connecting member 11 in the crown beam.

[0051] See also Figure 6 In step (b), the static pile driver 300 is sequentially installed on the upper side of the first beam hole 121 and the second beam hole 122 via the connecting piece, and the first steel pipe pile 21 and the second steel pipe pile 22 are respectively sunk into the ground through the first beam hole 121 and the second beam hole 122 by the static pile driver 300. Figure 8 When installing the static pile driver, the finely rolled threaded steel bars on the crown beam are passed through the bolt holes on the bottom plate 310 of the static pile driver 300, and then the bolts are screwed onto the finely rolled threaded steel bars. The static pile driver 300 is detachably installed on the crown beam via the finely rolled threaded steel bars. In subsequent construction, this method is used to install the static pile driver 300 on the crown beam. Figure 8 The bolts are not shown.

[0052] When sinking the first steel pipe pile 21 and the second steel pipe pile 22, since the deadweight of the static pile driver alone cannot fully bear the reaction force required for sinking the steel pipe piles, it is necessary to load a counterweight on the static pile driver to obtain sufficient reaction force. Of course, in other embodiments, other types of pile drivers can also be used to sink the first steel pipe pile 21 and the second steel pipe pile 22 into the ground.

[0053] The anti-pullout rod 32 is inserted into the hole 202 on the first steel pipe pile 21 and the second steel pipe pile 22, and the anti-pullout rod is located on the upper side of the crown beam. A steel pad 31 is placed between the anti-pullout rod and the crown beam, so that the anti-pullout rod is tightly pressed against the crown beam through the steel pad to avoid partial damage to the crown beam due to the reaction force in the subsequent construction, which affects the overall strength of the crown beam, and the steel pad is used to expand the contact area between the anti-pullout rod and the crown beam.

[0054] (1.2) Please refer to Figure 6 Please also refer to step (c) in Figure 7 and Figure 8 , transfer the static pile driver 300 to the position directly above the third beam hole 123 and install it on the crown beam 10, so that the static pile driver is located on the upper side of the third beam hole 123 adjacent to the second steel pipe pile 22 that has been completely sunk, and then use the static pile driver to sink the third steel pipe pile 23 into the ground through the third beam hole 123. When sinking the third steel pipe pile 23, the crown beam and the anti-pullout rod are pressed against each other, and the steel pipe pile that has been completely sunk is hooked on the crown beam through the anti-pullout rod, and the first steel pipe pile 21 and the second steel pipe pile 22 that have been completely sunk are used as reaction mechanisms to sink the third steel pipe pile into the ground. When sinking the third steel pipe pile 23, the anti-pullout rods on the first steel pipe pile 21 and the second steel pipe pile 22 are pressed against the lower end surface of the steel ring 201 at the same time, that is, when sinking the steel pile, the anti-pullout rod is pressed against the reinforcement. When sinking the third steel pipe pile, the static pile driver does not need a counterweight and can use the reaction force generated by the first steel pipe pile and the second steel pipe pile to sink the third steel pipe pile into the ground.

[0055] The anti-pullout rod 32 on the first steel pipe pile 21 is pulled out and inserted into the anti-pullout hole 202 of the third steel pipe pile 23, and the corresponding steel pad is transferred synchronously to reduce the number of anti-pullout rods and steel pads. That is, when more than two steel piles have been sunk, the anti-pullout rod on the steel pile far away from the pre-operation beam hole is transferred to the steel pile adjacent to the pre-operation beam hole, and when the anti-pullout rod is transferred, the corresponding steel pad is transferred synchronously. The third beam hole when sinking the third steel pipe pile is called the pre-operation beam hole.

[0056] (1.3) Please refer to Figure 6 Steps (d) and (e) in the above process are repeated until all the steel pipe piles are sunk. Figure 6 (d) is the state diagram after the fourth steel pipe pile is sunk. Figure 6Step (e) is the state diagram after the fifth steel pipe pile is sunk.

[0057] It can be understood that, in another embodiment, step (1.1) can also adopt the following steps:

[0058] Anchor rods are constructed in the construction area of ​​the preset positions of the first steel pipe pile and the second steel pipe pile, and then the static pile driver is installed on the anchor rods. The first steel pipe pile and the second steel pipe pile are then sunk to the preset positions using the static pile driver. The static pile driver is removed, and the crown beam is constructed. The first steel pipe pile and the second steel pipe pile are connected to the crown beam, and beam holes are reserved on the crown beam, and fine-rolled threaded steel bars are embedded. The first steel pipe pile and the second steel pipe pile pass through the crown beam upward. Of course, the construction of the first steel pipe pile and the second steel pipe pile can also be sunk by using pile drivers such as vibration and hammering. The connection between the first steel pipe pile and the second steel pipe pile and the crown beam can be made by using existing technology.

[0059] Insert the anti-pullout rod into the holes on the first steel pipe pile and the second steel pipe pile. The anti-pullout rod is located on the upper side of the crown beam. A steel pad is placed between the anti-pullout rod and the crown beam so that the anti-pullout rod is supported on the crown beam through the steel pad. Then, the above steps (1.2) and (1.3) are used to sink the remaining steel pipe piles.

[0060] It can be understood that in another embodiment, the steel pipe piles to be sunk can be divided into several groups, and then the steel pipe piles in each group are sunk using the above steps to improve the construction efficiency.

[0061] In step (1.1) of this embodiment, two steel pipe piles are sunk, namely the first steel pipe pile and the second steel pipe pile, and there is 0 beam holes between the first steel pipe pile and the second steel pipe pile, that is, when the number of the partial steel piles is 2, there is 0 beam holes between adjacent steel piles. It can be understood that in other embodiments, there can be 1, 2, 5 or 10 beam holes between the first steel pipe pile and the second steel pipe pile, or other numbers of beam holes between 1-10.

[0062] In step (1.1) of this embodiment, only two steel pipe piles are sunk. It can be understood that, depending on the difference in friction between the steel pipe piles and the underground soil, while satisfying the reaction force required for the sinking of the steel pipe piles, only one steel pipe pile can be sunk, or three or even more steel pipe piles can be sunk.

[0063] In this embodiment, two steel pipe piles are always used as the reaction force mechanism. It can be understood that in other embodiments, three, four or more steel pipe piles can also be used as the reaction force mechanism.

[0064] Example 2

[0065] See also Figure 3-Figure 5In this embodiment, the steel piles of the foundation pit support system are made of H steel, so the steel piles are called H steel piles 70. The H steel piles 70 have a web 711 and flanges 712 arranged on opposite sides of the web, and two anti-pullout holes B702 are arranged on each flange, and a flat steel plate 701 is welded on the inner wall of the flange as a reinforcement. Corresponding to each anti-pullout hole B702, a flat steel plate 701 is arranged. The flat steel plate is located on the upper side of the corresponding anti-pullout hole B, and the lower surface of the flat steel plate is at the same height as the uppermost end of the anti-pullout hole B, so that the anti-pullout rod B82 can be tightly pressed against the lower surface of the flat steel plate and the inner wall of the anti-pullout hole B at the same time. For clear display, Figure 3 In the embodiment, the anti-pullout rod B82 is inserted into only one anti-pullout hole B702, and the anti-pullout rod B82 in the other anti-pullout hole B702 is removed.

[0066] exist Figure 3 In the figure, only five through-beam holes B62 are shown on the crown beam B60 by way of example, four of which have H-steel piles 70 sunk into them. For the convenience of description, the four H-steel piles that have been sunk are sequentially referred to as the first H-steel pile 71, the second H-steel pile 72, the third H-steel pile 73 and the fourth H-steel pile 74.

[0067] The cross section of the beam-penetrating hole B is in an H shape, so that the beam-penetrating hole B has an inner peripheral surface with the same shape as the outer peripheral surface of the H steel pile.

[0068] The following briefly describes the construction method of the foundation pit support system in this embodiment. The construction method in this embodiment is the same as the construction method in Example 2. Figure 3 In the embodiment, the first H steel pile 71 and the second H steel pile 72 are sunk by a static pile driver with an added counterweight, which is the same as the sinking method of the first steel pipe pile 21 and the second steel pipe pile 22. The third H steel pile 73 is sunk by using the first H steel pile 71 and the second H steel pile 72 as reaction force. The fourth H steel pile 74 is sunk by using the second H steel pile 72 and the third H steel pile 73. The remaining H steel piles are sunk in sequence by using a similar method. Figure 3 In the embodiment, the steel plate B81 is used to replace the steel plate 31, and the anti-pullout rod B82 is used to replace the anti-pullout rod 32.

[0069] Example 3

[0070] This embodiment is an improvement on the embodiment 1. In this embodiment, some steel pipe piles are replaced by cast-in-place piles. Fig. 9In this embodiment, the foundation pit support system includes a crown beam 10, a cast-in-place pile 40 and a steel pipe pile C, wherein only the first steel pipe pile C41 is shown in the steel pipe pile C. The first steel pipe pile C is sunk into the ground through the first through-beam hole C51 adjacent to the cast-in-place pile 40, and the steel pipe piles C corresponding to the second through-beam hole C52, the third through-beam hole C53 and the fourth through-beam hole C54 have not yet been sunk. The structure of the steel pipe pile C in this embodiment is completely the same as that of the steel pipe pile in Example 1.

[0071] See also Fig.10 The foundation pit support system in this embodiment is constructed according to the following steps:

[0072] (2.1) Please refer to Fig.10 In step (a), a cast-in-place pile 40 is constructed, and then a crown beam 10 is constructed, so that the crown beam is connected to the cast-in-place pile 40, and a through-beam hole C is reserved on the crown beam 10, and each through-beam hole C passes through the upper surface and the lower surface of the crown beam 10. Fig.10 In the figure, only four beam-penetrating holes C are shown as examples. For the convenience of description, the four beam-penetrating holes C are respectively referred to as the first beam-penetrating hole C51, the second beam-penetrating hole C52, the third beam-penetrating hole C53 and the fourth beam-penetrating hole C54, wherein the first beam-penetrating hole C51 is adjacent to the cast-in-place pile 40. The crown beam is pre-embedded with a finely rolled threaded steel bar as a connecting member 11.

[0073] (2.2) Please refer to Fig.10 In step (b), the static pile driver is installed on the upper side of the first beam hole C51 via the connecting member 11, and the cast-in-place pile is used as a reaction force mechanism to sink the first steel pipe pile C41 into the ground through the first beam hole C51.

[0074] (2.3) Please refer to Fig.10 In step (c), the anti-pullout rod 32 is inserted into the pull-out hole on the first steel pipe pile C41, so that the anti-pullout rod 32 is located on the upper side of the crown beam, and a steel pad 31 is placed between the anti-pullout rod 32 and the crown beam 10, so that the anti-pullout rod is tightly pressed against the crown beam through the steel pad, and the static pressure pile driver is transferred to the upper side of the second through-beam hole C52, and the cast-in-place pile and the first steel pipe pile C41 are used together as a reaction mechanism to sink the second steel pipe pile C42 into the ground through the second through-beam hole C52.

[0075] (2.4) Please refer to Fig.10 In step (d), the anti-pullout rod 32 is inserted into the pull-out hole on the second steel pipe pile C42, so that the anti-pullout rod 32 is located on the upper side of the crown beam, and a steel pad 31 is placed between the anti-pullout rod 32 and the crown beam 10, so that the anti-pullout rod is tightly pressed against the crown beam through the steel pad, and the static pressure pile driver is transferred to the upper side of the third through-beam hole C53, and the cast-in-place pile, the first steel pipe pile C41 and the second steel pipe pile C42 are used as a reaction mechanism to sink the third steel pipe pile C43 into the ground through the third through-beam hole C53.

[0076] (2.5) Please refer to Fig.10 In step (e), the anti-pullout rod on the first steel pipe pile C41 is pulled out and inserted into the anti-pullout hole of the third steel pipe pile C43, and the steel pad corresponding to the first steel pipe pile C41 is transferred to the area opposite to the third steel pipe pile C43, and the static pressure pile driver is transferred to the upper side of the fourth through-beam hole C54, so that the anti-pullout rod is tightly pressed against the crown beam through the steel pad, and the cast-in-place pile, the second steel pipe pile C42 and the third steel pipe pile C43 are used together as a reaction mechanism to sink the fourth steel pipe pile C44 into the ground through the fourth through-beam hole C54.

[0077] (2.6) Repeat step (2.5) until all the steel pipe piles C are sunk.

[0078] In this embodiment, two steel pipe piles C are always kept connected to the crown beam as a part of the reaction mechanism. It can be understood that in other embodiments, one, three or more steel pipe piles C can also be always kept connected to the crown beam.

[0079] It is understood that in other embodiments, 2, 5, 10 or more cast-in-place piles may be constructed first, and 1-20 beam holes may be spaced between two adjacent cast-in-place piles. When only one beam hole is spaced between two adjacent cast-in-place piles, the construction is completed after the above step (2.2) is completed. When only two beam holes are spaced between two adjacent cast-in-place piles, the construction is completed after the above step (2.3) is completed. When only three beam holes are spaced between two adjacent cast-in-place piles, the construction is completed after the above step (2.4) is completed. When only four beam holes are spaced between two adjacent cast-in-place piles, the construction is completed after the above step (2.5) is completed. When the number of beam holes between two adjacent cast-in-place piles exceeds 4, the construction is completed after the above step (2.6) is completed. Of course, two cast-in-place piles can also be constructed continuously, that is, there is no through-beam hole between two adjacent cast-in-place piles. When the steel pipe pile C is sunk, the two cast-in-place piles are used as reaction force mechanisms.

[0080] It can be understood that when the steel pile is an H steel pile, the construction can be carried out with reference to the above construction method.

Claims

1. A foundation pit support system, characterized in that: It includes a crown beam and a steel pile. A through-beam hole is reserved on the crown beam and a connecting piece is embedded in the crown beam. The steel pile is sunk into the ground through the through-beam hole. An anti-pull-out hole is opened on the steel pile. The anti-pull-out rod can be inserted into the anti-pull-out hole and is located on the upper side of the crown beam. When the steel pile is sunk, the static pile driver is detachably installed on the crown beam via the connecting piece, and the anti-pull-out rod is pressed against the upper surface of the crown beam, so that the steel pile that sinks later can sink into the ground with the steel pile that sinks first as a reaction mechanism.

2. A foundation pit support system, characterized in that: It includes a crown beam, a cast-in-place pile and a steel pile. The crown beam is connected to the cast-in-place pile. A through-beam hole is reserved on the crown beam and a connecting piece is embedded in the crown beam. The steel pile is sunk into the ground through the through-beam hole. When the steel pile is sunk, the static pile driver is detachably mounted on the crown beam via the connecting piece, and the cast-in-place pile is used as a reaction mechanism to sink the steel pile into the ground. Or an anti-pull-out hole is opened on the steel pile, and an anti-pull-out rod can be inserted into the anti-pull-out hole and is located on the upper side of the crown beam. When the steel pile is sunk, the static pile driver is detachably mounted on the crown beam via the connecting piece, and the anti-pull-out rod is tightly pressed against the upper surface of the crown beam. The steel pile that sinks later can sink into the ground with the cast-in-place pile and the steel pile that sinks earlier acting as a reaction mechanism.

3. The foundation pit support system according to claim 1 or 2, characterized in that: When the anti-pullout rod is inserted into the anti-pullout hole, the anti-pullout rod is tightly pressed against the upper surface of the crown beam.

4. The foundation pit support system according to claim 3, characterized in that: A steel plate is laid on the upper surface of the crown beam, and the anti-pullout rod is tightly pressed against the steel plate.

5. The foundation pit support system according to claim 3, characterized in that: A reinforcement piece is fixed on the upper end of the steel pile. The reinforcement piece is located on the upper side of the anti-pullout hole, and the anti-pullout rod tightly presses the reinforcement piece thereon.

6. The foundation pit support system according to claim 1 or 2, characterized in that: The connecting piece is a precision-rolled threaded steel bar, and the precision-rolled threaded steel bar extends upward from the upper surface of the crown beam.

7. The foundation pit support system according to claim 1 or 2, characterized in that: The steel piles are steel pipe piles and / or H steel piles.

8. The foundation pit support system according to claim 1 or 2, characterized in that: The beam-penetrating hole has an inner peripheral surface having the same shape as the outer peripheral surface of the steel pile.

9. The foundation pit support system according to claim 2, characterized in that: One and only one cast-in-place pile is provided.

10. The foundation pit support system according to claim 2, characterized in that: At least two cast-in-place piles are provided, and 0-20 steel piles are arranged between two adjacent cast-in-place piles.

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