CN112813986A

CN112813986A - Deep foundation pit structure and deep foundation pit construction process

Info

Publication number: CN112813986A
Application number: CN202110011876.6A
Authority: CN
Inventors: 时云里; 杨耿; 刘体义; 吴炳辉; 李永飞; 庞超; 师鹏斌
Original assignee: China Eleventh Chemical Construction Co Ltd
Current assignee: China Eleventh Chemical Construction Co Ltd
Priority date: 2021-01-06
Filing date: 2021-01-06
Publication date: 2021-05-18

Abstract

The invention relates to the technical field of foundation pit excavation construction processes, in particular to a deep foundation pit structure and a deep foundation pit construction process. The deep foundation pit structure comprises a foundation pit, a positioning hole, a supporting pile, a crown beam and an anchoring assembly; the foundation pit is arranged on the side part of the original foundation bearing platform; the number of the positioning holes is multiple, and the positioning holes are arranged below the original foundation bearing platform at intervals and close to the foundation pit; the number of the supporting piles is multiple, and the supporting piles are formed by pouring concrete in the positioning holes in a one-to-one correspondence mode; the top beam is formed by pouring on the tops of all supporting piles and is supported at the bottom of the original foundation bearing platform; the anchoring component anchors soil bodies between adjacent supporting piles and the side walls of the supporting piles. The deep foundation pit construction process can construct and form the deep foundation pit mechanism, has the advantages of simple structure, easiness in construction, working procedure and construction period saving, normal operation of an original factory building device can be realized, production stop, dismantling and recovery can be avoided, and large economic loss can be generated, and economic benefits are also improved.

Description

Deep foundation pit structure and deep foundation pit construction process

Technical Field

The invention relates to the technical field of foundation pit excavation construction processes, in particular to a deep foundation pit structure and a deep foundation pit construction process.

Background

For large-scale petrochemical engineering and energy projects, reconstruction and extension projects in the original device area are very common. However, the reconstruction and extension projects are very close to the original device in position due to production process, site conditions and the like, and the construction of newly constructed underground foundations, especially underground deep foundations, is very difficult.

For example, in a technical transformation project of a thermal power plant, a new broken building is planned, the broken building project needs to arrange a raft underground, one side part of the raft is flush with the side surface of the foundation cushion cap of the original process pipe gallery, and the other side part of the raft is closer to the original underground gallery. In order to ensure the normal power generation operation of a thermal power plant, the normal operation of the original process pipe gallery and the original underground gallery needs to be ensured without being influenced in the process of carrying out construction of a crushing building.

In the face of the construction situation that the reconstruction and extension projects and the original device are very close to each other in position and narrow in space due to production processes, site conditions and the like, and particularly when deep foundation pit construction is carried out near the edge of the existing foundation and the difficulty is very high, the existing construction process cannot meet the construction requirement of normal operation of the original device.

Disclosure of Invention

The invention provides a deep foundation pit structure, which aims to solve the technical problems that in the prior art, under the condition that reconstruction and extension projects and an original device are close to each other or an existing foundation is performed near the edge, the deep foundation pit structure cannot meet the use requirement of the original device for normal operation.

The second objective of the present invention is to provide a deep foundation pit construction process, so as to solve the technical problem that the construction process cannot meet the use requirement of the normal operation of the original device even in the case that the reconstruction and extension projects and the original device are very close to each other or the existing foundation is performed near the edge in the prior art to a certain extent.

In order to achieve the above object, the present invention provides the following technical solutions;

based on the purpose, the deep foundation pit structure provided by the invention comprises a foundation pit, a positioning hole, a supporting pile, a crown beam and an anchoring assembly;

the foundation pit is arranged on the side part of the original foundation bearing platform;

the number of the positioning holes is multiple, and the positioning holes are arranged below the original foundation bearing platform at intervals and close to the foundation pit;

the number of the supporting piles is multiple, and the supporting piles are formed by pouring concrete in the positioning holes in a one-to-one correspondence mode;

the top beam is formed by pouring on the tops of all supporting piles and is supported at the bottom of the original foundation bearing platform;

the anchoring component anchors soil bodies between adjacent supporting piles and the side walls of the supporting piles.

In any of the above solutions, optionally, the anchor assembly includes a tie beam, a plurality of grouting holes, and a plurality of anchor lines;

the connecting beam is pressed on the side parts of all the supporting piles;

a grouting hole is formed in the soil body between the adjacent supporting piles, and the extension direction of the grouting hole forms an included angle of 10-20 degrees downwards with the horizontal direction;

one end of the anchor cable is anchored at the bottom of the grouting hole through mortar, and the other end of the anchor cable extends out of the grouting hole and is connected with the connecting beam in an anchoring mode.

In any of the above technical solutions, optionally, the deep foundation pit structure further includes a plurality of supporting assemblies;

the supporting components are sequentially connected from bottom to top and arranged between the inner wall of the positioning hole and the supporting pile.

In any of the above technical solutions, optionally, the supporting assembly includes a supporting plate and a cylindrical reinforcement cage; the cylindrical reinforcement cage comprises a main reinforcement, a reinforcing hoop and a binding piece;

the supporting plate is attached to the inner wall of the positioning hole, and the reinforcing hoop is horizontally arranged so that the supporting plate is clamped between the inner wall of the positioning hole and the reinforcing hoop;

the vertical setting of main muscle, the quantity of main muscle is a plurality of, and a plurality of main muscle are arranged along the circumference interval of strengthening the hoop, and the main muscle is all tied up fixedly through the strapping with the cross section of strengthening the hoop and strengthening the hoop with the cross section of a backplate.

Based on the second purpose, the deep foundation pit construction process provided by the invention is used for excavating a foundation pit at the side part of an original foundation bearing platform, and comprises the following steps:

pre-digging: digging a foundation pit with a preset depth under the side part of the original foundation bearing platform so as to expose the side wall of the original foundation bearing platform on the foundation pit;

digging a hole: a plurality of positioning holes are dug downwards below the original foundation bearing platform and close to the foundation pit, the positioning holes are arranged at intervals, and the depth of each positioning hole is not less than the target depth of the foundation pit;

pile forming: pouring concrete into the positioning holes to form support piles, and forming crown beams for supporting the original foundation bearing platform at the tops of all the support piles;

deep digging: continuously excavating a foundation pit downwards from the foundation pit until the depth of the foundation pit reaches the target depth;

rope distribution: in the deep digging process, the soil body between the side wall of the supporting pile and the adjacent supporting pile is anchored through the anchoring component.

In any of the above technical solutions, optionally, along the horizontal direction, a portion of the positioning hole corresponds to the original foundation bearing platform, and another portion of the positioning hole is exposed from the original foundation bearing platform;

and/or in the deep excavation process, when the preset depth is excavated downwards, the supporting piles are exposed out of the soil body between the bottom end edge of the side wall of the foundation pit and the adjacent supporting piles through the anchoring components to be anchored.

In any of the above technical solutions, optionally, the step of forming the pile specifically includes:

and (3) supporting: sequentially fixing a plurality of supporting components on the inner wall of the positioning hole from the bottom to the top of the positioning hole, and forming a pouring space inside the supporting components;

pouring: and pouring concrete into the pouring space to form the support pile in the pouring space.

the supporting step specifically comprises:

densely distributing the supporting and protecting plates along the inner wall of the positioning hole;

horizontally placing the reinforcing hoop in the positioning hole so that the supporting plate is clamped between the inner wall of the positioning hole and the reinforcing hoop;

the reinforcing hoop and the supporting plate are fixedly bound through a binding piece;

the main reinforcement is vertically placed, and the main reinforcement and the reinforcement hoop are bundled and fixed through the bundling piece to form a cylindrical reinforcement cage.

In any of the above solutions, optionally, the main bars of adjacent support assemblies are welded to each other.

In any of the above technical solutions, optionally, the step of routing specifically includes:

downwards deviating by 10-20 degrees in the horizontal direction, and drilling and excavating a plurality of grouting holes into soil between adjacent support piles;

simultaneously pushing one end of the grouting pipe and one end of the anchor cable into the bottom of the grouting hole;

grouting the bottom of the grouting hole through the grouting pipe until the mortar reaches the orifice of the grouting hole, and taking out the grouting pipe;

and after anchoring all the anchor cables and the soil body, pressing the connecting beam to the side parts of all the supporting piles, and anchoring the other ends of all the anchor cables and the connecting beam.

By adopting the technical scheme, the invention has the beneficial effects that:

the deep foundation pit structure provided by the invention comprises a foundation pit, a positioning hole, a supporting pile, a crown beam and an anchoring assembly; the foundation pit is arranged on the side part of the original foundation bearing platform; the number of the positioning holes is multiple, and the positioning holes are arranged below the original foundation bearing platform at intervals and close to the foundation pit; the number of the supporting piles is multiple, and the supporting piles are formed by pouring concrete in the positioning holes in a one-to-one correspondence mode; the top beam is formed by pouring on the tops of all supporting piles and is supported at the bottom of the original foundation bearing platform; the anchoring component anchors soil bodies between adjacent supporting piles and the side walls of the supporting piles. Thereby can consolidate the below that original basic cushion cap is close to the foundation ditch through a plurality of support piles, crown beam and anchor subassembly, improve the stability of original basic cushion cap, can guarantee that the excavation of foundation ditch does not influence the normal operation of the original factory building device that original basic cushion cap supported. In addition, because original basic cushion cap has obtained reinforcement treatment for the foundation ditch can regard original basic cushion cap as the lateral wall, that is to say, the lateral wall that foundation ditch and original basic cushion cap are adjacent need not put the slope, and then makes and adopts not putting the slope excavation when excavating the foundation ditch with original basic cushion cap local cross in narrow and small place and become possible. This deep basal pit simple structure, easily construction practices thrift process and time limit for a project, and former factory building device can normal operating, can avoid stopping production, demolish and resume and produce great economic loss, has also improved economic benefits.

The deep foundation pit construction process provided by the invention is used for constructing and forming the deep foundation pit structure, so that all beneficial effects of the deep foundation pit structure can be realized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic view of a first structure of a deep foundation pit structure according to a first embodiment of the present invention;

fig. 2 is a second structural schematic view of a deep foundation pit structure according to a first embodiment of the present invention;

fig. 3 is a schematic structural diagram of a support pile and an anchor assembly of a deep foundation pit structure according to an embodiment of the present invention;

fig. 4 is a partial enlarged view of fig. 3 at a.

Icon: 1-deep foundation pit structure; 10, a foundation pit; 11-supporting piles; 12-a crown beam; 13-an anchoring assembly; 130-tie beam; 131-anchor cable; 132-a limit stop; 2-original basic bearing platform; 3-original plant equipment.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example one

Referring to fig. 1 to 4, the present embodiment provides a deep foundation pit structure.

The deep foundation pit structure 1 provided by the embodiment comprises a foundation pit 10, a positioning hole, a support pile 11, a crown beam 12 and an anchoring assembly 13.

The foundation pit 10 is arranged on the side part of the original foundation bearing platform 2, the foundation pit 10 is directly arranged on the side part of the original foundation bearing platform 2, slope-releasing excavation construction is not needed, the space of the side part of the original foundation bearing platform 2 is fully utilized, and the foundation pit 10 can be excavated in sequence under the extremely narrow condition of the field space.

The number of the positioning holes is multiple, the positioning holes are arranged below the original foundation bearing platform 2 at intervals and close to the foundation pit 10, and the soil body between the adjacent positioning holes can still provide a vertical supporting effect for the original foundation bearing platform 2.

The number of the supporting piles 11 is multiple, the supporting piles 11 are formed by pouring concrete in the positioning holes in a one-to-one correspondence mode, and the crown beams 12 are poured and formed on the tops of all the supporting piles 11 and supported at the bottom of the original foundation bearing platform 2. The crown beam 12 and all the supporting piles 11 are connected to form a whole, so that the whole formed by the crown beam 12 and the supporting piles 11 provides more reliable support for the part, close to the foundation pit 10, below the original foundation bearing platform 2, and the purpose of reliably reinforcing the original foundation bearing platform 2 is achieved. It is worth emphasizing that the supporting strength is improved because the integral formed by the supporting piles 11 and the crown beams 12 replaces the original soil body in the positioning holes, so that the stability of the original foundation bearing platform 2 can be obviously improved after being reinforced.

The anchoring component 13 anchors the soil between the adjacent supporting piles 11 and the side walls of the supporting piles 11, so that the whole formed by all the supporting piles 11 and the crown beams 12 and the soil between the adjacent supporting piles 11 further form a whole, the anchoring component 13 tensions the supporting piles 11 and the crown beams 12 towards the side of the original foundation bearing platform 2, the phenomenon that the whole formed by the supporting piles 11 and the crown beams 12 is toppled over is avoided, namely the supporting piles 11 and the original foundation bearing platform 2 form a whole, the reinforcing effect of the deep foundation pit structure on the original foundation bearing platform 2 is further improved, and the normal operation of the original factory building device 3 supported by the original foundation bearing platform 2 is ensured.

In the present embodiment, the anchor assembly 13 includes a tie beam 130, a plurality of grout holes, and a plurality of anchor lines 131.

The connecting beam 130 is pressed on the side of all the supporting piles 11; a grouting hole is formed in the soil body between the adjacent supporting piles 11, and the extension direction of the grouting hole forms an included angle of 10-20 degrees downwards with the horizontal direction; one end of the anchor cable 131 is anchored at the bottom of the grouting hole through mortar, and the other end of the anchor cable 131 extends out of the grouting hole and is anchored and connected with the connecting beam 130. The tensile force applied to the connecting beam 130 by the anchor cable 131 is directed to the inside of the soil body along the extending direction of the grouting hole, and the extending direction of the grouting hole forms a downward included angle of 10-20 degrees with the horizontal direction, so that the tensile force can be decomposed into a first component force perpendicular to the outer side wall of the connecting beam 130 and directed to the inside of the soil body, and a second component force downward along the vertical direction, so that the connecting beam 130 compresses all the support piles 11 together towards the inside of the soil body through the first component force, and downward pressure is applied to the support piles 11 through the second component force, so that the bottoms of the support piles 11 are connected with the soil body more stably, and compared with a connection mode in which an included angle is formed upwards, an upward second component force can be avoided, and further the second component force is prevented from playing a role of pulling up the support piles 11.

Specifically, the anchor assembly 13 further includes a stopper 132, and the stopper 132 is connected to the other end of the anchor cable 131 and pressed against the outer side of the connection beam 130, so as to fix and connect the other end of the anchor cable 131 and the connection beam 130.

Alternatively, the limiting member 132 has a wedge shape, a vertical wall surface of the limiting member 132 contacts an outer side of the connection beam 130, and an inclined wall surface of the limiting member 132 is perpendicular to an extending direction of the anchor cable 131, so as to stably fix the anchor cable 131.

In this embodiment, the deep foundation pit structure 1 further includes a plurality of support members. And the plurality of supporting components are sequentially connected from bottom to top and are arranged between the inner wall of the positioning hole and the supporting pile 11.

In order to avoid the looseness of the hole wall of the positioning hole and ensure the structural strength of the supporting pile 11, a supporting component is arranged between the inner wall of the positioning hole and the supporting pile 11. In addition, the target depth of the foundation pit 10 can reach tens of meters or even tens of meters in general, so in order to reduce the supporting difficulty, a plurality of supporting components are sequentially connected from bottom to top for supporting.

In this embodiment, the supporting assembly comprises a supporting plate and a cylindrical reinforcement cage; the cylindrical reinforcement cage comprises a main reinforcement, a reinforcing hoop and a binding piece. The supporting plate is attached to the inner wall of the positioning hole, the reinforcing hoop is horizontally arranged, so that the supporting plate is clamped between the inner wall of the positioning hole and the reinforcing hoop, the reinforcing hoop can play a role in positioning the supporting plate, and the supporting plate is prevented from toppling inwards.

The vertical setting of main muscle, the quantity of main muscle is a plurality of, and a plurality of main muscle are arranged along the circumference interval of strengthening the hoop, and the main muscle is all tied up fixedly through the strapping with the cross section of strengthening the hoop and strengthening the hoop with the cross section of a backplate. The reinforcing hoop and the supporting plate are bound and fixed through the binding piece, so that the reinforcing hoop can be prevented from sliding down and up; through setting up the main muscle to make main muscle and reinforcement form vertically and horizontally staggered's tube-shape steel reinforcement cage through the strapping, carry out three-dimensional location to the supporting plate through the tube-shape steel reinforcement cage, improve the anti deformability of whole supporting component, in order to guarantee follow-up supporting pile 11's smooth shaping.

Example two

The second embodiment provides a deep foundation pit construction process, the deep foundation pit structure in the first embodiment can be formed by the deep foundation pit construction process provided by the first embodiment, the technical features of the deep foundation pit structure disclosed in the first embodiment are also applicable to the first embodiment, and the technical features of the deep foundation pit structure disclosed in the first embodiment are not described repeatedly.

With reference to fig. 1 to 4, the deep foundation pit construction process provided in this embodiment is used to excavate a foundation pit at a side portion of an original foundation cap. The original basic bearing platform is a structure which is located underground and plays a bearing role in the original factory building.

In the related art, when the existing foundation is constructed with a deep foundation pit near the edge, in order to ensure the construction safety, a frequently used method is to temporarily remove or translate the original plant device supported by the original foundation bearing platform, and restore the original appearance after the construction of the building in the deep foundation pit is finished and the foundation pit is backfilled. The construction method adopting the scheme has the problem that a foundation pit is excavated on the side part of the original basic bearing platform of the original process pipe gallery by taking a certain thermal power plant as an example so as to newly build a broken building seat on the foundation pit. Original technology piping lane is the key facility that provides steam to other apparatus for producing, and original technology piping lane is from demolising to final recovery completion, and the process increases, and the time limit for a project is longer, and during whole new broken building project construction, the steam power plant will be in the off-stream state always, and the normal production of other apparatus for producing that the direct impact relies on steam power plant steam has caused very big economic loss. On the other hand, the cost of secondary recovery after the original plant device is dismantled is high, which causes great cost loss. In addition, when the original plant device is dismantled and foundation pit excavation is carried out, because the depth of the foundation pit exceeds 16m, in order to reduce the risk of failure of the original foundation bearing platform of the original plant device, a foundation pit side slope needs to be adopted at the edge close to the original foundation bearing platform, the foundation pit side slope still needs to be supported in the modes of soil nailing walls, side slope spray anchoring and the like, and great expense is caused.

With reference to fig. 1 to 4, the deep foundation pit construction process provided in this embodiment includes the following steps:

step 100, pre-digging: digging a foundation pit with a preset depth under the side part of the original foundation bearing platform so as to expose the side wall of the original foundation bearing platform on the foundation pit;

step 110, hole digging: a plurality of positioning holes are dug downwards below the original foundation bearing platform and close to the foundation pit, the positioning holes are arranged at intervals, and the depth of each positioning hole is not less than the target depth of the foundation pit;

step 120, forming a pile: pouring concrete into the positioning holes to form support piles, and forming crown beams for supporting the original foundation bearing platform at the tops of all the support piles;

step 130, deep digging: continuously excavating a foundation pit downwards from the foundation pit until the depth of the foundation pit reaches the target depth;

step 140, rope distribution: in the deep digging process, the soil body between the side wall of the supporting pile and the adjacent supporting pile is anchored through the anchoring component.

In this embodiment, before digging the hole, dig in advance earlier, dig in advance the basic foundation ditch that obtains only need make original basic cushion cap 2 the lateral part expose can, not only can not influence original basic cushion cap 2's stability because the basic foundation ditch is too deep, but also can be convenient for constructor dig the hole operation.

Before deep excavation, a plurality of positioning holes are excavated below the original foundation bearing platform 2, the positioning holes are arranged at intervals, soil between the adjacent positioning holes after hole excavation can still provide a supporting effect in the vertical direction for the original foundation bearing platform 2, and the soil below the foundation pit can also provide a lateral supporting effect for an original foundation adult, so that the stability of the original foundation bearing platform 2 cannot be influenced in the hole excavation process.

In the pile forming step, the supporting piles 11 are formed by pouring concrete, the top parts of the supporting piles 11 are provided with the crown beams 12 in a forming mode, and the crown beams 12 are connected with all the supporting piles 11 to form a whole, so that the whole formed by the crown beams 12 and the supporting piles 11 is close to the foundation pit below the original foundation bearing platform 2, and the purpose of reliably reinforcing the side parts of the original foundation bearing platform 2 is achieved.

Alternatively, the number of the crown beams 12 may be plural, and each of the crown beams 12 connects a part of the support piles 11 among all the support piles 11 at the same time.

In the excavation process of the foundation pit 10, soil bodies on the side portion of the original foundation bearing platform 2 need to be excavated, and due to the narrow space and the inability of slope setting, the original supporting effect of the excavated soil bodies on the original foundation bearing platform 2 disappears, after the original foundation bearing platform 2 is reinforced through the pile forming step, deep excavation is performed on the side portion of the original foundation bearing platform 2, and the problem that the stability of the original foundation bearing platform 2 is affected due to the excavation of the soil bodies below the foundation pit can be effectively avoided.

In the deep digging process, the side wall of the supporting pile 11 and the soil body between the adjacent supporting piles 11 are anchored through the anchoring component 13, the whole formed by all the supporting piles 11 and the crown beam 12 and the soil body between the adjacent supporting piles 11 can further form a whole, the anchoring component 13 tensions the supporting piles 11 and the crown beam 12 towards the side where the original foundation bearing platform 2 is located, the whole formed by the supporting piles 11 and the crown beam 12 is prevented from falling, namely the supporting piles 11 and the original foundation bearing platform 2 form a whole, the stability of the original foundation bearing platform 2 in the deep digging process is further improved, and therefore the normal operation of the original plant building device 3 supported by the original foundation bearing platform 2 is ensured.

The deep foundation pit construction process is particularly suitable for excavation of a deep foundation pit 10 in a narrow space under the gobi geological condition, the construction process and the obtained deep foundation pit structure have high reliability, non-stop construction can be achieved, economic benefits are remarkable, the concept of green construction scientific development is met, and large-dismantling and large-building of the original device is avoided. In addition, the method is simple and convenient to operate, the construction period is shortened, safety and reliability are realized, and the method can be widely applied to the petrochemical industry, the coal chemical industry and the energy project transformation and upgrading project.

In the present embodiment, along the horizontal direction, a portion of the positioning hole corresponds to the original foundation platform 2, and another portion of the positioning hole is exposed from the original foundation platform 2. In the step of digging the hole, manual excavation can be adopted, one part of the positioning hole is arranged below the original foundation bearing platform 2, and the other part of the positioning hole is arranged outside the original foundation bearing platform 2, so that excavated earthwork can be transported outwards, and sediments at the bottom of the hole of the positioning hole can be cleaned. Optionally, the positioning holes are located below the original foundation cap 2 along at least half of the radial direction thereof to ensure support stability.

In this embodiment, the deep foundation pit construction process provided by this embodiment includes the following steps:

step 200, pre-digging: digging a foundation pit with a preset depth under the side part of the original foundation bearing platform so as to expose the side wall of the original foundation bearing platform on the foundation pit;

step 210, hole digging: a plurality of positioning holes are dug downwards below the original foundation bearing platform and close to the foundation pit, the positioning holes are arranged at intervals, and the depth of each positioning hole is not less than the target depth of the foundation pit;

step 220, supporting: sequentially fixing a plurality of supporting components on the inner wall of the positioning hole from the bottom to the top of the positioning hole, and forming a pouring space inside the supporting components;

step 230, pouring: pouring concrete into the pouring space to form support piles in the pouring space, and forming crown beams for supporting the original foundation bearing platform on the tops of all the support piles;

step 240, deep digging: continuously excavating a foundation pit downwards from the foundation pit until the depth of the foundation pit reaches the target depth;

step 250, rope distribution: in the deep digging process, the soil body between the side wall of the supporting pile and the adjacent supporting pile is anchored through the anchoring component.

In this embodiment, in order to avoid loosening of the wall of the positioning hole and ensure the structural strength of the supporting pile 11, the supporting pile 11 is cast after the supporting component supports the side wall of the positioning hole. Specifically, in order to ensure the stability of the bottom of the support pile 11 fixed in the soil body, the depth of the positioning hole is not less than the target depth of the foundation pit 10, and generally, the target depth of the foundation pit 10 can reach dozens of meters or even dozens of meters, so in order to reduce the supporting difficulty, a mode of sequentially connecting a plurality of supporting components from bottom to top is adopted for supporting.

In an alternative of this embodiment, the supporting assembly includes a supporting plate and a cylindrical reinforcement cage; the cylindrical reinforcement cage comprises a main reinforcement, a reinforcing hoop and a binding piece.

The supporting step specifically comprises:

step 221, densely distributing the supporting and protecting plates along the inner wall of the positioning hole;

step 222, horizontally placing the reinforcing hoop in the positioning hole so that the supporting plate is clamped between the inner wall of the positioning hole and the reinforcing hoop;

step 223, the reinforcing hoop and the supporting plate are fixedly bound through the binding piece;

and 224, vertically placing the main reinforcement, and binding and fixing the main reinforcement and the reinforcing hoop through a binding piece to form the cylindrical reinforcement cage.

In this embodiment, the inner wall of the positioning hole is shaped and protected by the supporting and protecting plate; the supporting and protecting plate is pressed on the positioning hole through the reinforcing hoop to play a role in positioning, so that the supporting and protecting plate is prevented from falling inwards; the reinforcing hoop and the supporting plate are bound and fixed through the binding piece, so that the reinforcing hoop can be prevented from sliding down and up; through setting up the main muscle to form vertically and horizontally staggered's tube-shape steel reinforcement cage with the reinforcement hoop, improve the anti deformability of whole supporting subassembly, with the smooth of the follow-up stake 11 process of pouring of supporting of assurance.

Wherein, weld the steel bar into the loop configuration with the same size matching of locating hole shape, can obtain the reinforcement hoop in the locating hole, compare in direct with the strengthening rib from the outer construction mode of whereabouts to the locating hole in of locating hole, reduced the transportation degree of difficulty, and carry out the location connection through the mode that the strapping member tied up, easy operation, the connection is reliable, can improve the efficiency of construction on guaranteeing to strut the subassembly and have abundant anti deformability's basis, shortens and struts the time limit for a project.

In particular, in order to improve the deformation resistance and the positioning capability of the reinforcement cage, on the one hand, the intersection between the main bar and the reinforcement hoop is welded. Further, quincunx spot welding is carried out at the intersection between the reinforcing hoop and the main rib every 1-1.5m along the vertical direction. Furthermore, the earring positioners are used for positioning at the intersections of the main ribs and the reinforcing ribs every 5m in the vertical direction, two earring positioners can be used for positioning at each intersection in a cross shape, and the specification of the earring positioners is phi 20 so as to keep the protective layer at 5-6 cm.

Optionally, the supporting plate is formed by a 2 cm-thick pine plate, the reinforcing hoops are made of phi 18 threaded steel, the distance between every two adjacent reinforcing hoops is 50cm along the vertical direction, and the height of each supporting component is not more than 1 m.

Optionally, in order to improve the pouring effect of the support pile 11, firstly, sediment, floating soil and the like at the bottom of the positioning hole are cleaned, then, aggregate with the thickness not greater than 20mm and concrete with the slump of 20-30cm are poured into the positioning hole in a grading manner, the height of the poured concrete is not greater than 1.5m each time, after the pouring is completed each time, the concrete is vibrated and compacted by a column type vibrating bar and is not self-obtained by falling, and the pouring of the support pile 11 can be completed in a layering manner until the concrete is poured into the positioning hole to the target height. The pouring of the supporting pile 11 is carried out by the construction method, so that the strength performance of the supporting pile 11 can be ensured to be enough to stably reinforce the original foundation bearing platform 2.

In this embodiment, in order to improve the integrity of all the supporting assemblies, the main bars of the adjacent supporting assemblies are welded to each other, so that the supporting assemblies on the upper layer can be prevented from sliding downwards and sinking, and the positioning performance of each layer of supporting assemblies can be improved.

In this embodiment, the step of routing specifically includes the following steps:

251, shifting downwards by 10-20 degrees in the horizontal direction, and drilling grouting holes in soil bodies between adjacent support piles;

step 252, simultaneously pushing one end of the grouting pipe and one end of the anchor cable into the bottom of the grouting hole;

step 253, grouting the bottom of the grouting hole through the grouting pipe until the mortar reaches the orifice of the grouting hole, and taking out the grouting pipe;

and 254, after anchoring all the anchor cables and the soil body, pressing the connecting beam to the side parts of all the supporting piles, and anchoring the other ends of all the anchor cables and the connecting beam.

In the present embodiment, a plurality of anchoring relationships are formed between the supporting piles 11 and the original foundation cap 2 in the horizontal upward direction, so that the three-dimensional property and uniformity of the arrangement of the anchoring relationships are improved.

When the grouting holes are drilled and dug, a drilling machine is required to drill and dig in soil bodies between the adjacent supporting piles 11, drill rods needed for drilling are placed in order according to the designed length of the anchor cable 131, the drill rods are guaranteed to be right in place when the drill holes are used up, and the drilling and digging efficiency of the grouting holes is improved.

During grouting, mortar is injected from the bottom of the grouting hole, air is discharged from a gap between the grouting pipe and the grouting hole, and when the opening of the grouting hole begins to emit the mortar, the mortar is indicated to be filled in the grouting hole, and the grouting pipe can be drawn out.

Because the anchoring process between the anchor cable 131 and the soil body is more complicated, the construction method of firstly anchoring the anchor cable 131 and the soil body and then anchoring the anchor cable 131 and the connecting beam 130 facilitates the formation of a structure for anchoring through the plurality of anchor cables 131 and the connecting beam 130, so that the construction process is more reasonable and scientific.

Specifically, the cement mortar adopted for grouting requires a water cement ratio of 0.4-0.5; the ratio of the ash to the sand is 1: 1. Grouting needs to be carried out by adopting a grouting machine, and the grouting pressure is kept at 0.3-0.6 MPa.

Specifically, the length of each anchor cable 131 is 18m, and the aperture of the grouting hole is Φ 200.

Optionally, the depth of the grouting hole exceeds the designed length of the anchor cable 131 by about 0.5cm, and a floating allowance of the anchor cable 131 is reserved.

Alternatively, in order to secure anchoring stability of the anchor line 131 in each grouting hole, a plurality of anchor lines 131 may be anchored in each grouting hole.

Optionally, the declination angle of the grouting hole is 10 °, 12 °, 15 °, 17 °, 19 ° or 20 °, and the molding error of the declination angle of the grouting hole is not more than 1 °.

Optionally, the soil mass between each two support piles 11 is drilled with grouting holes, so that the soil mass between each two support piles 11 is integrally connected with the support piles 11 through the tie beams 130 and the anchor cables 131.

In the present embodiment, during the deep excavation process, each time a predetermined depth is excavated, the support piles 11 are exposed to the soil body between the bottom end edge of the side wall of the foundation pit 10 and the adjacent support piles 11 and anchored by the anchoring assemblies 13.

Specifically, in the direction of height, set up first anchor subassembly 13 from crown beam 12 top 4m department down, continue to set up one down every 2m to on the basis that the horizontal direction formed many places anchor, further form many places anchor in the direction of height, be favorable to improving the wholeness along the direction of height between original basic cushion cap 2 and the support stake 11, and then further improve the structural stability of the limit portion of original basic cushion cap 2 and this foundation ditch 10.

Optionally, since the position of the supporting pile 11 prone to toppling is at the top rather than at the bottom, only three anchoring assemblies 13 need to be arranged at the top of the supporting pile 11, so that the usage amount of the anchoring assemblies 13 and the construction period of anchoring construction can be saved as much as possible on the basis of meeting the anchoring requirement.

The deep foundation pit construction process in the embodiment has the advantages of the deep foundation pit structure in the first embodiment, and the advantages of the deep foundation pit structure disclosed in the first embodiment are not described repeatedly herein.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention. Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Claims

1. A deep foundation pit structure is characterized by comprising a foundation pit, a positioning hole, a supporting pile, a crown beam and an anchoring assembly;

2. The deep foundation pit structure of claim 1, wherein the anchor assembly comprises a tie beam, a plurality of grout holes and a plurality of anchor lines;

the connecting beam is pressed on the side parts of all the supporting piles;

3. The deep foundation pit structure of claim 1, further comprising a plurality of support assemblies;

4. The deep foundation pit structure of claim 3, wherein the support assembly comprises a support plate and a cylindrical reinforcement cage; the cylindrical reinforcement cage comprises a main reinforcement, a reinforcing hoop and a binding piece;

5. The deep foundation pit construction process is characterized by being used for excavating a foundation pit at the side part of an original foundation bearing platform and comprising the following steps of:

6. The deep foundation pit construction process according to claim 5,

along the horizontal direction, one part of the positioning hole corresponds to the original foundation bearing platform, and the other part of the positioning hole is exposed out of the original foundation bearing platform;

7. The deep foundation pit construction process according to claim 5, wherein the pile forming step specifically comprises:

8. The deep foundation pit construction process according to claim 7, wherein the support assembly comprises a support plate and a cylindrical reinforcement cage; the cylindrical reinforcement cage comprises a main reinforcement, a reinforcing hoop and a binding piece;

the supporting step specifically comprises:

9. The deep foundation pit construction process according to claim 8,

and welding the main bars of the adjacent supporting assemblies.

10. The deep foundation pit construction process according to claim 5, wherein the cable arranging step specifically comprises: