Disclosure of Invention
The invention aims to provide a foundation pit excavation supporting system and a construction method of an up-through subway tunnel, which can improve the stability of a foundation pit structure, improve the accuracy of the driving and positioning of supporting piles and improve the structural integrity.
In order to achieve the purpose, the technical scheme provides an excavation supporting system of a foundation pit of an upper-penetrating subway tunnel and a construction method, and the excavation supporting system comprises the following construction steps:
1) construction preparation: determining the shape parameters of the support pile through site survey, and preparing materials and devices required by construction;
2) dividing an excavation block: according to the stability control requirement, determining the plane distribution of the separating piles and the circumferential piles of the supporting piles respectively, and dividing the foundation pit soil body to be excavated into 2 or 4 or 6 excavation blocks;
3) and (3) guide driving of a support pile: respectively arranging a guide partition plate on two sides of the separation pile and the annular pile along the arrangement direction of the separation pile and the annular pile, and firmly connecting a partition plate positioning plate with soil around the pile through a partition plate anchor bar; adopting a supporting pile construction device to carry out supporting pile construction;
4) pouring the pile top crown beam: arranging a crown beam bottom support plate at the top end of the guide partition plate, controlling the positions of a crown beam bottom die and a crown beam side die by the crown beam bottom support plate and the crown beam side support plate through a template positioning bolt respectively, and arranging a template connecting groove on the crown beam bottom die; carrying out concrete pouring construction on the pile top crown beam; arranging a foundation pit inner support between pile top crown beams at the top ends of the support piles;
5) and (3) excavating soil in the excavation block in a layering manner: dividing the soil body in each excavation block into 4 layers from top to bottom, dividing each layer into 3 blocks, and excavating the soil body according to the principle of 'firstly digging two sides and then digging middle'; when the soil body is excavated to be below the elevation of the inner supporting beam, a lower layer supporting plate and an upper layer supporting plate are arranged on the side of the supporting pile, which is far away from the soil body around the pile, and the lower layer supporting plate and the upper layer supporting plate are firmly connected with the supporting pile through supporting plate anchor bars; placing the beam position control body in the guide position control groove, and arranging a beam hoop on the inner support beam; connecting external hoisting equipment with hoisting rings on the beam hoops, hoisting the inner supporting beam to a position between the opposite beam position control bodies, and applying jacking force to the inner supporting beam through the beam position control bodies; a beam support rib is arranged between the beam hoop and the upper layer supporting plate;
6) and (3) pit bottom pressing bottom plate construction: the pit bottom pressure bottom plate comprises a cast-in-place pressure bottom plate and a prefabricated pressure bottom plate, the prefabricated pressure bottom plate is firstly constructed, and the cast-in-place pressure bottom plate is cast; arranging a cast-in-place pressure bottom plate on the inner side of the support pile along the annular direction, and arranging a prefabricated pressure bottom plate in an annular space formed by enclosing the cast-in-place pressure bottom plate; leading holes from the inner side wall of the support pile to the soil body around the pile, inserting the grouting anchor pipe into the soil body around the pile, grouting the grouting anchor pipe through an external grouting equipment part, and forming anchoring grouting body around the grouting anchor pipe in the soil body around the pile; firmly connecting the integral connecting plate with the support pile through an anchor pipe bolt, and driving a post-positioned anchor bar from the integral connecting plate to the support pile; firstly, carrying out drainage cushion layer construction on the upper surface of a pit bottom soil body, then carrying out binding construction of a bottom plate longitudinal bar and a bottom plate stirrup, and firmly connecting a post-positioned anchor bar with the bottom plate longitudinal bar through an anchor bar connecting bolt; firstly, according to the plane position requirement of the prefabricated pressure bottom plate, the prefabricated pressure bottom plate is laid, an inter-plate sealing body is arranged at the vertical joint of the lower step, the position of a top mold of the pressure bottom plate is limited through a top mold position control bolt on a top mold position control connecting plate, and then cast-in-place pressure bottom plate pouring construction is carried out; after the prefabricated plate connecting ribs are firmly connected through the inter-plate fastening bolts, pouring construction of the inter-plate reinforcement is carried out;
7) pit bottom pressure bottom plate back pressure: laying a seam cushion layer on the upper surface of the pit bottom pressing plate, arranging back pressure blocks under the inner supporting beam, arranging a pressurizing bag between the adjacent back pressure blocks, injecting pressurized slurry into the pressurizing bag through a bag grouting pipe, and synchronously applying vertical pressure to the back pressure supporting columns and the back pressure blocks through the back pressure control bodies;
8) and (3) inner support replacement construction: when the main structure of the tunnel in the foundation pit is constructed, the plate top bearing plate and the cast-in-place pressure base plate as well as the beam side bearing plate and the pile top crown beam are firmly connected through the bearing plate anchor bars respectively, and the plate top bearing plate and the beam side bearing plate are connected with the diagonal bracing support beam through the support beam rotating shaft; connecting the inclined supporting beam and the vertical supporting beam with the same axis through a supporting beam rotating shaft; pile side back pressure bodies are arranged between the vertical supporting beams and the annular piles, and then the separating piles and the inner supporting beams are dismantled.
Compared with the prior art, the technical scheme has the following characteristics and beneficial effects:
(1) according to the invention, the foundation pit to be excavated is divided into 2 or 4 or 6 excavation blocks through the dividing piles and the circumferential piles, each excavation block is divided into 4 layers along the vertical direction, each layer is divided into 3 blocks, soil body excavation is carried out according to the principle of 'firstly carrying out two sides and then carrying out middle', the soil pressure in the excavation process can be effectively reduced, the stability of the foundation pit structure is improved, and the disturbance of the foundation pit excavation on the surrounding soil body is reduced.
(2) The driving direction of the separation pile and the circumferential pile is limited by the guide partition plate, so that the accuracy of driving and positioning the support pile is improved; meanwhile, the supporting and locating of the side die and the bottom die of the crown beam are carried out by the aid of the bottom bracing plate of the crown beam outside the guide partition plate, and the supporting and locating difficulty of the formwork of the crown beam is reduced.
(3) The integral connecting plate and the support pile are firmly connected through the grouting anchor pipe and the anchoring grouting body, and the post anchor rib and the bottom longitudinal rib are connected into a whole through the anchor rib connecting bolt, so that the concentrated stress of a joint part can be greatly reduced, and the integrity of the structure is enhanced; meanwhile, the vertical position of the top die of the pressure bottom plate is limited by the top die position control bolt, so that downward pressure can be applied to the poured concrete, and the compactness of the cast-in-place pressure bottom plate is improved.
(4) The pit bottom pressure bottom plate comprises a cast-in-place pressure bottom plate and a prefabricated pressure bottom plate, the cast-in-place pressure bottom plate is arranged on the inner side of the supporting pile along the circumferential direction, and the prefabricated pressure bottom plate is arranged in an annular space formed by the cast-in-place pressure bottom plate in a surrounding mode, so that the field construction efficiency can be greatly improved; meanwhile, the prefabricated pressing bottom plates are provided with joint connecting tenons and joint mortises, and prefabricated plate connection and inter-plate reinforcement bodies are arranged between the connected prefabricated pressing bottom plates, so that the connection strength and the structural integrity between the prefabricated plates can be improved.
(5) The pit bottom pressure plate is subjected to back pressure by the back pressure block and the back pressure bag together, and the back pressure control body can be used for applying down pressure to the back pressure block, so that the difficulty of back pressure construction of the pressure plate is reduced, and the supporting effect of the inner supporting cross beam can be exerted.
(6) According to the invention, the pile side counter pressure body is arranged between the vertical supporting beam and the circumferential pile, and the transverse force of the vertical supporting beam can be transmitted to the pile top crown beam and the cast-in-situ pressure bottom plate through the oblique supporting beam, so that the difficulty of support replacement construction is reduced.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
The technical requirements of profile steel rolling and welding construction, bolt fastening construction, support pile construction, site hoisting construction, concrete pouring construction and the like are not repeated in the embodiment, and the embodiment of the method is mainly explained.
Fig. 1 is a construction flow chart of excavation and support of a foundation pit of an upper-through subway tunnel, and referring to fig. 1, the construction method of the excavation and support system of the foundation pit of the upper-through subway tunnel comprises the following construction steps:
1) construction preparation: determining the shape parameters of the support pile 1 through site survey, and preparing materials and devices required by construction;
2) dividing an excavation block: according to the stability control requirement, the plane distribution of the separating piles 2 and the circumferential piles 3 of the supporting piles 1 is respectively determined, the foundation pit soil body to be excavated is divided into 2 or 4 or 6 excavation blocks 4, wherein the circumferential piles 3 are arranged around the excavation blocks 4, and the separating piles 2 are arranged in the circumferential piles 3 to divide the foundation pit soil body into a plurality of excavation blocks 4;
3) and (3) guide driving of a support pile: respectively arranging a guide partition plate 5 on two sides of the separation pile 2 and the annular pile 3 along the arrangement direction of the separation pile 2 and the annular pile 3, and firmly connecting a partition plate positioning plate 7 on the side of the guide partition plate 5 with a pile surrounding soil body 8 through a partition plate anchor bar 6; the construction of the supporting pile 1 is carried out by adopting a supporting pile construction device, specifically, a partition plate positioning plate 7 is welded at the side of a guide partition plate 5, a hole is formed on the partition plate positioning plate 7, and a partition plate anchor bar 6 is inserted into the hole of the partition plate positioning plate 7 and fixed in a soil body 8 around the pile;
4) pouring the pile top crown beam: arranging a crown beam bottom bracing plate 9 at the top end of the guide partition plate 5, controlling the positions of a crown beam bottom mould 12 and a crown beam side mould 13 by the crown beam bottom bracing plate 9 and the crown beam side bracing plate 10 through a mould plate position correcting bolt 11 respectively, and arranging a mould plate connecting groove 64 on the crown beam bottom mould 12; performing concrete pouring construction of the pile top crown beam 14 between the crown beam side forms 13 on the two sides; arranging a foundation pit inner support 15 between pile top crown beams 14 at the top ends of the support piles 1;
the crown beam side supporting plate 10 is vertically arranged on the side of the crown beam bottom supporting plate 9, the crown beam bottom supporting plate 9 and the crown beam side supporting plate 10 are supported by inclined supports 59 of the supporting plates in an inclined manner, the crown beam bottom die 12 is arranged on the crown beam bottom supporting plate 9 through a template positioning bolt 11 and is arranged on the inner side of the crown beam side supporting plate 10, the crown beam side die 13 is vertically arranged on the crown beam bottom die 12, and the crown beam side die 13 and the crown beam side supporting plate 10 are connected through the template positioning bolt 11; the guide partition plates 5 on both sides of the support pile 1 are symmetrically arranged so that the support pile 1 is positioned between the crown beam side molds 13 on both sides.
Wherein the foundation pit inner support 15 is arranged in the excavation block 4 and is obliquely arranged.
5) And (3) excavating soil in the excavation block in a layering manner: dividing the soil body in each excavation block 4 into 4 layers from top to bottom, dividing each layer into 3 blocks, and excavating the soil body according to the principle of 'firstly digging two sides and then digging middle'; when the soil body is excavated to the position below the elevation of the inner supporting beam 16, a lower layer supporting plate 17 and an upper layer supporting plate 18 are arranged on the side of the supporting pile 1 departing from the soil body 8 around the pile, the lower layer supporting plate 17 and the upper layer supporting plate 18 are firmly connected with the supporting pile 1 through supporting plate anchor bars 19, and the supporting plate anchor bars 19 penetrate through the lower layer supporting plate 17 and the upper layer supporting plate 18 and are fixed on the supporting pile 1; the beam control body 20 is arranged in a guide control groove 21 on the side of a lower layer supporting plate 17, a beam hoop 22 is arranged on an inner supporting beam 16, external hoisting equipment is connected with a hoisting hanging ring 65 on the beam hoop 22, the inner supporting beam 16 is hoisted to a position between the opposite beam control bodies 20, jacking force is applied to the inner supporting beam 16 through the beam control body 20, and a beam support rib 58 is arranged between the beam hoop 22 and an upper layer supporting plate 18;
6) and (3) pit bottom pressing bottom plate construction: the pit bottom pressure bottom plate 23 comprises a cast-in-place pressure bottom plate 24 and a prefabricated pressure bottom plate 25, the prefabricated pressure bottom plate 25 is firstly constructed, then the cast-in-place pressure bottom plate 24 is cast, the cast-in-place pressure bottom plate 24 is arranged on the inner side of the support pile 1 along the circumferential direction, and the prefabricated pressure bottom plate 25 is arranged in an annular space formed by the cast-in-place pressure bottom plate 24 in a surrounding mode;
the grouting anchor pipe 26 is inserted into the pile surrounding soil body 8 from the inner side wall of the support pile 1 to the inner hole of the pile surrounding soil body 8 on the other side, then the grouting anchor pipe 26 is grouted through an external grouting equipment part, the anchoring grouting body 28 is formed at the periphery of the grouting anchor pipe 26 in the pile surrounding soil body 8, the integral connecting plate 30 and the support pile 1 are firmly connected through the anchor pipe bolt 29, and the rear anchor rib 31 is arranged from the integral connecting plate 30 to the support pile 1 to strengthen the connection firmness of the integral connecting plate 30 and the support pile 1.
Firstly, constructing a drainage cushion layer 33 on the upper surface of a pit bottom soil body 32 on the inner side of the support pile 1, and then performing binding construction of a bottom plate longitudinal rib 34 and a bottom plate stirrup 35, wherein the bottom plate longitudinal rib 34 is arranged in parallel with the pit bottom soil body 32, a plurality of bottom plate longitudinal ribs 34 are bound through the bottom plate stirrup 35, and the rear anchor rib 31 is firmly connected with the bottom plate longitudinal rib 34 through an anchor rib connecting bolt 36 on the bottom plate longitudinal rib 34.
Firstly, according to the plane position requirement of the prefabricated pressure bottom plate 25, the prefabricated pressure bottom plate 25 is laid, an inter-plate airtight body 37 is arranged at a vertical joint of a lower-layer step of the prefabricated pressure bottom plate 25, the position of a pressure bottom plate top mold 40 is limited through a top mold position control bolt 39 arranged on a top mold position control connecting plate 38 on an integral connecting plate 30, and then the pouring construction of a cast-in-place pressure bottom plate 24 is carried out on the lower surface of the pressure bottom plate top mold 40; after the prefabricated plate connecting ribs 42 of the prefabricated pressing bottom plates 25 are firmly connected through the inter-plate fastening bolts 41, pouring construction of inter-plate reinforcement 43 is carried out between the prefabricated pressing bottom plates 25;
7) pit bottom pressure bottom plate back pressure: firstly, laying a layer of seam cushion layer 44 on the upper surface of the pit bottom pressing plate 23, then arranging a back pressure block body 45 below the inner supporting beam 16, arranging the back pressure block body 45 on the seam cushion layer 44, arranging a pressurizing bag 46 between adjacent back pressure block bodies 45, injecting pressurized slurry 48 into the pressurizing bag 46 through a bag grouting pipe 47 on the pressurizing bag 46, synchronously applying vertical pressure on a back pressure support column 50 and the back pressure block body 45 through a back pressure control body 49 on the inner supporting beam 16, wherein the back pressure control body 49 is arranged on the lower surface of the inner supporting beam 16, the back pressure control body 49 is connected with the back pressure support column 50, and the back pressure support column 50 is arranged on the back pressure block body 45;
8) and (3) inner support replacement construction: when the tunnel main body structure in the foundation pit is constructed, the plate top bearing plate 52 and the cast-in-place pressure base plate 24 are firmly connected through the bearing plate anchor bars 51, the beam side bearing plate 53 and the pile top crown beam 14 are firmly connected, the plate top bearing plate 52, the beam side bearing plate 53 and the diagonal bracing beam 54 are connected through the bracing beam rotating shaft 55, and the diagonal bracing beam 54 and the vertical bracing beam 56 in the same axis are connected through the bracing beam rotating shaft 55; pile side counter-pressure bodies 57 are arranged between the vertical supporting beams 56 and the circumferential piles 3, and then the separation piles 2 and the inner supporting beams 16 are removed.
In step 3), the guide partition plate 5 adopts the steel sheet rolling to form, and the bottom inserts in the all soil body 8 of stake, sets up perpendicular welded connection's baffle locating plate 7 with it along the even interval of 5 length direction of guide partition plate, baffle locating plate 7 adopts the steel sheet rolling to form, sets up the hole that supplies baffle anchor bar 6 to wear to establish on it, separate stake 2 and hoop 3 and adopt bored concrete pile or cement mixing pile, wherein separate stake 2 and be used for separating excavation block 4, hoop 3 is the hoop along treating excavation foundation ditch all around and lays.
In the step 4), the crown beam bottom bracing plate 9 and the crown beam side bracing plate 10 are formed by rolling steel plates, the crown beam bottom bracing plate 9 is vertically welded with the guide partition plate 5, a bracing plate inclined support 59 is arranged between the crown beam bottom bracing plate 9 and the crown beam side bracing plate 10, the template positioning bolt 11 comprises a screw and a bolt, and the fastening directions of the screws on the two sides of the bolt are opposite.
In the step 5), the upper supporting plate 18 and the lower supporting plate 17 are both formed by rolling steel plates, the cross section of each supporting plate is arc-shaped, the central angle is 45-60 degrees, the inner diameter of each supporting plate is the same as the outer diameter of the connected supporting pile 1, holes for the supporting plate anchor bars 19 to penetrate through are formed in each supporting plate, the guide position control grooves 21 are formed by rolling steel plates, the cross sections of the guide position control grooves are U-shaped, one ends of the guide position control grooves are vertically welded with the lower supporting plate 17, and the other ends of the guide position control grooves are free.
In the step 6), the cross section of the integral connecting plate 30 is arc-shaped, the central angle is 45-60 degrees, holes for the grouting anchor pipes 26 and the rear anchor bars 31 to penetrate are formed in the integral connecting plate 30, and the integral connecting plate is vertically welded and connected with the top die position control connecting plate 38.
The mud jacking anchor pipe 26 is formed by rolling a steel pipe, a mud jacking hydraulic outlet 63 is formed in the side wall of the mud jacking anchor pipe and is connected with the support pile 1 in a grouting mode, the rear anchor bar 31 is formed by rolling a steel pipe or a steel bar and is connected with the integral connecting plate 30 in a welding mode and connected with the bottom plate longitudinal bar 34 through an anchor bar connecting bolt 36, the top mold position control bolt 39 is formed by rolling a screw rod and is connected with the top mold position control connecting plate 38 through threads.
The prefabricated pressure bottom plate 25 is prefabricated by reinforced concrete materials, the periphery of the prefabricated pressure bottom plate is provided with connecting steps 27, a lower step is provided with a joint tenon 60 and a joint tenon groove 61, an upper step is provided with a prefabricated plate connecting rib 42, and a lower step connected with the cast-in-place pressure bottom plate 24 is provided with an inter-plate reinforcing rib 62 connected with a bottom plate longitudinal rib 34 or a bottom plate stirrup 35; the cross sections of the joint tenon 60 and the joint mortise 61 are isosceles trapezoids, and the joint tenon 60 and the joint mortise 61 are respectively arranged on two mutually parallel surfaces of the prefabricated pressing bottom plate 25.
Step 7), the joint cushion layer 44 is made of geotextile or medium coarse sand or cement mortar material; the back pressure block body 45 is a concrete precast block and is arranged right below the inner supporting cross beam 16, and a back pressure support column 50 and a back pressure position control body 49 are sequentially arranged between the back pressure block body and the inner supporting cross beam 16; the counter pressure control body 49 adopts a hydraulic jack.
And 8) adopting section steel or a hydraulic jack to vertically connect the pile side counter pressure body 57 with the annular pile 3.
Referring to fig. 2 to 10, in the excavation and support system of the foundation pit of the upper-penetrating subway tunnel, a foundation pit to be excavated is divided into 2 or 4 or 6 excavation blocks 4 through dividing piles 2 and circumferential piles 3, each excavation block 4 is excavated vertically in 4 layers, each layer is divided into 3 blocks, and soil excavation is performed according to the principle of firstly digging two sides and then digging the middle; the driving direction of the support pile 1 is limited by a guide clapboard 5 arranged at the sides of the separation pile 2 and the circumferential pile 3, and a clapboard positioning plate 7 at the side of the guide clapboard 5 is firmly connected with a soil body 8 around the pile; utilizing a supporting pile construction device to perform concrete pouring construction on pile top crown beams 14 on the top sides of the supporting piles 1, wherein the pile top crown beams 14 are connected through foundation pit inner supports 15; the integral connecting plate 30 is firmly connected with the support pile 1 through a mud jacking anchor pipe 26 and an anchoring mud jacking body 28, a pit bottom pressing plate 23 is constructed on the side of the support pile 1, back pressure is carried out on the pit bottom pressing plate 23, and the vertical position of a pressing plate top die 40 is limited through a top die position control bolt 39; the pit bottom pressing bottom plate 23 comprises a cast-in-place pressing bottom plate 24 and prefabricated pressing bottom plates 25, and prefabricated plate connecting ribs 42 and an inter-plate reinforcement 43 are arranged between the connected prefabricated pressing bottom plates 25; the pit bottom pressure plate 23 is subjected to back pressure by adopting the back pressure block body 45 and the pressurizing bag 46 together; between the vertical support beams 56 and the circumferential piles 3 pile side counter-pressure bodies 57 are arranged.
The support pile 1 comprises a separation pile 2 and a circumferential pile 3, and is a concrete cast-in-place pile with the diameter of 1000mm, wherein the separation pile 2 is used for separating an excavation block 4, and the circumferential pile 3 is arranged along the circumferential direction of a foundation pit to be excavated.
The excavation block 4 is divided into four blocks, and the length and the width are respectively as follows: 15m is multiplied by 13m, 16m is multiplied by 13m, 15m is multiplied by 14m, 16m is multiplied by 14m, and the excavation is divided into 4 layers along the vertical direction, and each layer is divided into 3 blocks.
The guide partition plate 5 is formed by rolling a steel plate with the thickness of 10mm, the bottom end of the guide partition plate is inserted into a soil body 8 around the pile, partition plate positioning plates 7 which are vertically welded and connected with the guide partition plate are arranged at even intervals along the length direction of the guide partition plate 5, the partition plate positioning plates 7 are formed by rolling the steel plate with the thickness of 10mm, and holes for the partition plate anchor bars 6 to penetrate are formed in the partition plate positioning plates. Wherein, the baffle anchor bars 6 adopt threaded ribbed steel bars with the diameter of 32 mm.
The soil body 8 around the pile is sandy soil in a medium density state.
The crown beam bottom supporting plate 9 and the crown beam side supporting plate 10 are both formed by rolling steel plates with the thickness of 10mm, the crown beam bottom supporting plate 9 is vertically welded and connected with the guide partition plate 5, and a supporting plate inclined support 59 is arranged between the crown beam bottom supporting plate 9 and the crown beam side supporting plate 10; the bracing plate oblique supports 59 are made of steel pipes with the diameter of 60 mm.
The template position-correcting bolt 11 comprises a high-strength screw rod with the diameter of 30mm and a bolt, and the fastening directions of the screw rods on the two sides of the bolt are opposite.
The crown beam bottom die 12 and the crown beam side die 13 are both formed by rolling steel plates with the thickness of 10 mm.
The pile top crown beam 14 is cast by concrete with the strength grade of C35.
The foundation pit inner support 15 and the inner support cross beam 16 both adopt H-shaped steel with the specification of 250 multiplied by 9 multiplied by 14.
The upper layer supporting plate 18 and the lower layer supporting plate 17 are both formed by rolling steel plates with the thickness of 10mm, the cross section of each supporting plate is arc-shaped, the central angle of each supporting plate is 60 degrees, the inner diameter of each supporting plate is the same as the outer diameter of the connected supporting pile 1, and holes for the supporting plate anchor bars 19 to penetrate through are formed in the supporting plates; the supporting plate anchor bars 19 adopt threaded ribbed steel bars with the diameter of 32 mm.
The beam control body 20 adopts a self-locking hydraulic jack of 100 tons.
The guiding position control groove 21 is formed by rolling a steel plate with the thickness of 10mm, the cross section of the guiding position control groove is U-shaped, and one end of the guiding position control groove is vertically welded and connected with the lower supporting plate 17.
The cross beam anchor ear 22 is formed by rolling a steel plate with the thickness of 2mm, is sleeved on the outer side of the inner supporting cross beam 16, has the length of 30cm, is firmly connected with the cross beam anchor ear 22 and the inner supporting cross beam 16 through bolts, and is provided with a hoisting hanging ring 65 on the top surface; the hoisting hanging ring 65 is formed by rolling a steel bar with the diameter of 32mm and is vertically welded with the cross beam hoop 22.
The pit bottom pressure soleplate 23 comprises a cast-in-situ pressure soleplate 24 and a prefabricated pressure soleplate 25, wherein the cast-in-situ pressure soleplate 24 is formed by casting concrete with the strength grade of C35, and the thickness of the cast-in-situ pressure soleplate is 30 cm; the prefabricated pressing bottom plate 25 is prefabricated by reinforced concrete materials, and the thickness is 30 cm; the prefabricated pressure bottom plate 25 is all provided with connecting steps 27 around, the height of the lower step and the height of the upper step are both 15cm, the lower step is provided with a joint tenon 60 and a joint tenon groove 61, the upper step is provided with a prefabricated plate connecting rib 42, and the lower step connected with the cast-in-situ pressure bottom plate 24 is provided with an inter-plate reinforcing rib 62 connected with the bottom plate longitudinal rib 34 or the bottom plate stirrup 35. The width of the middle platform of the connecting step 27 is 100mm, the precast slab connecting rib 42 and the inter-slab reinforcing rib 62 are respectively formed by rolling a screw rod with the diameter of 30mm and a threaded steel bar with the diameter of 32mm, and the bottom plate longitudinal rib 34 and the bottom plate stirrup 35 are respectively formed by rolling a threaded ribbed steel bar with the diameter of 32mm and a threaded ribbed steel bar with the diameter of 10 mm.
The cross sections of the joint tenon 60 and the joint mortise 61 are isosceles trapezoids, the top width is 10cm, the bottom width is 20cm, and the height is 5 cm.
The anchoring grout 28 is cement mortar.
The anchor pipe bolt 29 is composed of a high-strength screw rod and a bolt with the diameter of 30 mm.
The integral connecting plate 30 is formed by rolling a steel plate with the thickness of 10mm, the cross section of the integral connecting plate is in a circular arc shape, the central angle of the integral connecting plate is 60 degrees, and holes for the grouting anchor pipes 26 and the rear anchor bars 31 to penetrate are formed in the integral connecting plate 30 and are vertically welded and connected with the top die position control connecting plate 38. Wherein, the top mould position control connecting plate 38 is formed by rolling a steel plate with the thickness of 10mm, the mud jacking anchor pipe 26 is a steel pipe with the inner diameter of 60mm, a mud hydraulic outlet 63 is arranged on the side wall of the mud jacking anchor pipe, the outer surface of the mud hydraulic outlet is connected with the support pile 1 through glue injection, and the diameter of the mud hydraulic outlet 63 is 20 mm.
The rear anchor bar 31 is formed by rolling a screw rod with the diameter of 30mm, is welded with the integral connecting plate 30, is connected with the bottom plate longitudinal bar 34 through an anchor bar connecting bolt 36, and the anchor bar connecting bolt 36 adopts a nut matched with the rear anchor bar 31.
The drainage cushion layer 33 is made of medium coarse sand material and has the thickness of 10 cm.
The interpanel closing body 37 is cut out from a rubber plate having a thickness of 10 mm.
The top die position control bolt 39 is formed by rolling a screw rod with the diameter of 30mm and is connected with the top die position control connecting plate 38 through threads.
The pressure bottom plate top die 40 is formed by rolling a steel plate with the thickness of 3 mm.
The inter-plate fastening bolts 41 adopt nuts matched with the precast slab connecting ribs 42.
The inter-plate reinforcement 43 is formed by pouring self-compacting impermeable concrete with the strength grade of C35.
The seam pad 44 is made of geotextile material.
The back
pressure block body 45 is a concrete precast block, is a cuboid, is arranged right below the inner supporting
beam 16, and is sequentially provided with a back
pressure supporting column 50 and a back pressure
position control body 49 between the inner supporting
beam 16. Wherein, the back pressure
position control body 49 adopts a hydraulic jack, and the back
pressure support column 50 adopts a strength grade of Q345D and has the specification of
The steel pipe of (2).
The pressurizing bag 46 is sewn by a rubber sheet having a thickness of 2 mm.
The bladder grouting pipe 47 is a PVC pipe having an inner diameter of 60 mm.
Tap water was used as the pressurized slurry 48.
The bearing plate anchor bars 51 are high-strength screws with a diameter of 30 mm.
The plate top bearing plate 52 and the beam side bearing plate 53 are both formed by rolling steel plates with the thickness of 10 mm.
The diagonal bracing beams 54 and the vertical bracing beams 56 are both rolled by H-shaped steel with the specification of 200 multiplied by 8 multiplied by 12.
The strut beam rotating shaft 55 is a universal joint coupling of the type MVJSS 20.
The pile side counter-pressure body 57 is connected vertically to the circumferential pile 3 by a 10-ton hydraulic jack.
The beam brace 58 is made of a steel pipe with an inner diameter of 60 mm.
The template attachment slots 64 are 4mm wide and 1mm high.
The present invention is not limited to the above-mentioned preferred embodiments, and any other products in various forms can be obtained by anyone in the light of the present invention, but any changes in the shape or structure thereof, which have the same or similar technical solutions as those of the present application, fall within the protection scope of the present invention.