126results about How to "Reduce post-construction settlement" patented technology

A method for reinforcement of yielding soil of large area or hollow land includes the following procedures in order: 1. low position vacuum pre-press procedure as building cofferdam, filling in sludge to certain height, paving cloth and bamboo fence on the top, vertically inserting in water emission plastic boards, laying horizontal vacuum pipe net, installing vacuum pre-press system and sealing with mud layer of 0.8-1.5 m thick then vacuum bumping for pre-press; 2. high vacuum rate well point water reduction procedure as applying a high vacuum rate well point water reduction system on the mud sealing layer, removing well point pipe after the first round of water reduction; 3. low power strong tamping procedure as paving a layer of filling material on the mud sealing layer then tamping. Roller compact the surface after 2-3 rounds of procedure 2 and 3.

The invention discloses a bidirectional vacuum pre-pressing hydraulically-filled soft ground treatment process, which comprises the following steps that building sealing walls and embedding vacuum pipes on the bottom of a coffer-dam, paving sand cushion with appropriate thickness whose inner portion is provided with filter strainers and vacuum tubes, and the surface is covered with earth-work cloth, building plastic drainage plates whose one section which is exposed on the surface of earth is vertically tied on a bamboo frame upwards, hydraulically filling sands to height mark, installing vacuum-pumping devices, and paving vacuum films. And the process is finished after the design consolidation degree is reached on the earth through starting the vacuum-pumping pump. The process increases the reinforcing treatment depth of vacuum pre-pressing, shortens the construction cycle of hydraulically-filled earth-building project, and saves vacuum film material.

The invention relates to a forming bore equipment with concrete sealing, pipe pile with cap and wing, and construction technology. The equipment is connected with Vibration joint 1 in upper position. The middle part is cavity structure, comprised by inner and outer sleeving 2, 3, with stayed bar. Nether shoe structure is comprised of many sections, which connect inner and outer sleeving 2, 3. Fixed section 5 with convex pillar is welded with inner and outer 2, 3. One end of active section 6 is connected with outer sleeving 3 and iron hinges 7. Two hyperbaric injecting pipes 11, through which concrete is injected into bottom of pipe pile and cavity and sprayed to soil surrounding pipe pile so as to form wing 17, are set outside it. Cavity structure is extracted and reinforcing cage is pressed-in. Cap 13 is added to the tip of pile and sandrock layer 14 and earth grid 15 are lay. It is provided with improving single pile load, reducing pile quantity and so on, and has widely applications.

The invention discloses a method for processing vehicle bump at a bridge head of an existing highway, and the method comprises the following steps: mixing lightweight materials at a construction site; drilling holes from embankment slopes on both sides of the highway, and automatically discharging soil outward from a threaded opening while rotatably drilling holes; after a designed depth reaches, rotatably and slowly pulling out a drill rod, and starting a booster pump so as to pump the lightweight materials into the obtained drill holes by virtue of a central tube of the drill rod; and jetting the lightweight materials from the central hole of the drill rod so as to gradually fill the hole from bottom to top, thereby replacing the filled soil of an embankment. The drill holes are arranged squarely or quincuncially on the side slope of the embankment, a certain included angle is formed between each drill hole and a horizontal plane, and the elevation of the opening of each hole is positioned below a pavement structure layer and above the underside of the filled soil of the embankment. By using the method disclosed by the invention, the weight of the embankment is greatly reduced, thereby reducing the settlement after construction caused by embankment loads and then effectively solving the problem of vehicle bump at bridge heads. During the construction period, the highway is not required to be closed, therefore, the normal traffic of the highway is not affected. The method disclosed by the invention is simple in construction process, convenient to operate, simple in equipment, economical, and high in efficiency.

The invention discloses a method for processing a soft ground by rapid pressurizing pre-compression, which is characterized by comprising the following steps: (1) arranging a vertical drainage system in a stratum, arranging a horizontal water collecting and drainage rough sand layer and horizontal drainage pipes on ground surface, and burying vibrators at certain intervals while arranging the vertical drainage system; and (2) while applying a static drainage consolidation method, starting the vibrators to make soft soil generate a high pore water pressure that is superposed with a pressure generated by the static drainage consolidation method to drain water in the soft soil quickly. Compared with the conventional vacuum pre-compression or preloading, the method can reduce construction period by more than 1 / 3, improve consolidation and reduce after-construction settlement and cost.

The invention relates to a construction method of a spiral oil-extruding filling pile composite foundation in the stratum containing soft clay, which comprises the following steps: determining the structural size, the position and the number of spiral oil-extruding filling piles; manufacturing and constructing a vertical drainage well in the middle part of the design positions of every two adjacent spiral oil-extruding filling piles; manufacturing and constructing each spiral oil-extruding filling pile according to the design position in the middle part between every two finished vertical drainage wells; and then paving drain liner layers on the foundation surface. The invention aims at providing a method for treating the spiral oil-extruding filling pile composite foundation in the stratum containing the soft clay, which avoids the negative oil-extruding effect of the spiral oil-extruding filling piles, improves the drain speed of saturated clay around piles, improves the strength of soil bodies around the piles and under the piles, substantially reduces the settlement after construction, improves the effectiveness and the use range of the spiral oil-extruding filling piles, increases the space length between the piles, reduces the pile number, saves the engineering investment, and accelerates the construction progress.

The invention in a technical sphere of soft soil ground treatment in geotechnical engineering relates to a soil ground treatment method in the areas along the sea, the river and the lake. The invention combines a vacuum drainage, a compaction via vibration supercharging, and a compaction via dynamic consolidation supercharging, wherein a higher kinetic head gradient which is consisted of a positive pressure of excess pore water by vibration excitation and a vacuum negative pressure firstly discharges the water in soil and increases the water content in the soil, thereby compacting the soil to a certain extend, and then the dynamic consolidation action is proceeded to improve the excess pore water pressure and form the higher kinetic head gradient thereby draining and compacting the soil. All the steps are proceeded many times to eliminate the settling of the worked deep layer soft soil and to improve surface consolidation degree, intensity, and stiffness until up the design requirement. Compared with the present method, the invention not only has a short time for a project, lower manufacturing cost and settling after work, and a good effect of consolidating and compacting, but also is extensive used in the soft soil ground treatment of various projects in the area along the sea, the river, or the like.

The invention discloses an ultra-deep T-shaped trench-wall pile in a soft-toped hard-bottomed soil layer and a trench forming method. The trench forming method includes the steps: firstly, pre-reinforcing soft soil at each external corner of a T-shaped trench wall; secondly, digging a guide wall foundation pit, treating the extremely soft soil layer at the bottom area of a guide wall to lead the bearing capacity of the foundation bottom of the guide wall to be larger than or equal to 100kPa; and thirdly using the trench forming way of 'drilling and gripping'. By the method, trench forming efficiency can be improved greatly, cost is lowered, and evident economy is achieved.

The invention relates to a drainage consolidation method without keeping drainage channel after work of a soft soil foundation, which can be recycled by a system. The method comprises the following steps of: impacting to form a hole by using a high pressure gun; pressing and burying a vertical drain filter pipe into the hole; connecting a flexible seepage filer pipe with the vertical drain filter pipe; connecting the other end of the flexible seepage filter pipe with a horizontal branch drain; connecting the horizontal branch drain with a horizontal main drain; paving geotextiles, and paving vacuum films on the geotextiles; connecting the horizontal main drain with a vacuum pump for vacuumizing; and detaching the parts, filling left holes, filling slag, excavating gutters, and impacting and compacting the slag layer by using impact compactor. The method overcomes the respective defects of the pile foundation technology, composite foundation technology and consolidated drained technology. In the method, recyclable vertical drainage filter pipe and horizontal main and branch drain structures are adopted, the construction cost is reduced, the field settlement after work is decreased, the transmission channel for vacuum pressure is widened, and the consolidation speed of the reinforced soil is improved.

The invention relates to a large-area soft soil foundation duplex negative consolidation processing method, comprising the following processes of: step 1, negative pressure consolidation: (a) paving plastic woven cloths in an area to be processed, driving a vertical plastic drainage board and a vertical plastic soak-away trench; (b) paving a main pipe and a branch pipe, wherein the vertical plastic drainage board and a transverse plastic drainage board are connected with the branch pipe; (c) paving a geo-membrane, and paving two to three sealing membranes on the geo-membrane; (d) excavating a side ditch pressing membrane; (e) installing a vacuum pump to vacuumize for negative pressure precipitation, wherein the main pipe is connected with the vacuum pump; step 2, well point dynamic arrangement: (a) inserting a well point pipe in a hole inserted by a vertical plastic soak-away trench or nearby the hole; (b) paving the branch pipe, the main pipe and the vacuum pump, carrying out the well point dynamic arrangement; and step 3, dynamic consolidation: a) precipitating and dynamically compacting in the first and second times, carrying out precipitation and dynamic compaction processes on the area to be processed for several times, carrying out multiple rounds of point compactions and finally carrying out a full compaction. According to the large-area soft soil foundation duplex negative consolidation processing method, the bearing capacity of the processed field is higher, the hard crust is thicker and the post-construction settlement is less.

Disclosed is a combined-type composite foundation with controllable rigidity piles, drainage materials and a reinforced cushion. The reinforced cushion is laid on the surface of a soft soil foundation. The vertical drainage materials and the rigidity piles with caps are arranged in the foundation. Grouting tubes are installed between pile tops and the pile caps to form a controllable supporting system. When grouting is not conducted on the grouting tubes, drainage consolidation is conducted through the soft soil foundation under the effect of an upper load so as to improve the bearing capacity. The bearing effect of the rigidity piles is difficult to play due to the fact that the rigidity piles are stabbed into the grouting tubes. When the grouting tubes are grouted and after slurry is hardened, the pile caps, the slurry and the rigidity piles form a rigidity support, and the goal that the load is undertaken by the piles and soil together to reduce settlement is realized. Meanwhile, the reinforced cushion has the effects of restraining the horizontal displacement of the piles and the soil, limiting the local deformation of a dyke and a dam and the like. According to the composite foundation, the bearing force of the foundation soil can be given full play; the using amount of the rigidity piles is reduced; the stability of the foundation is improved; the post-construction settlement and differential settlement are reduced; the construction period is shortened; and the composite foundation can be applied to projects such as highways, railways and earth-rock dams.

The invention relates to a quick ''low level high-vacuum hierarchical precompression compaction' method for soft ground, the concretely processes are: 1) a sand layer is laid on the ground before filling, then the plastic water discharging boards are inserted vertically, a high vacuum precompression system is arranged transversely in the sand layer, and a layer of plastic air isolating film is covered; 2) the high vacuum precompressing system carries on vacuum and precompression; 3) the sand blowing high vacuum compacting system is arranged on the film transversely or vertically; 4) fills sand on the film to the set height; 5) the high vacuum precompression system carries on precompressing to the set boding rate, the system carries on the first time of vacuuming and discharge, then carries on the first time of compacting or vibration compacting the sand on the film; 6) carries on the second time or several times of 'high vacuum compacting' to the sand to the overconsolidation state. The invention is short period, low price, and the quality is controllable.

The invention provides a double-layer low level vacuum preloading consolidation device and a soft soil foundation consolidation method. The device consists of a main controller, a power distribution controller, a vacuum pump, a submersible pump, a buffer knockout drum, a control valve, a vacuum gauge, a vacuum degree detecting head, a hydraulic fill consolidation layer vacuum pipe network, a soft soil consolidation layer vacuum pipe network, a subsidence mark, an open water overflow port, pipes and gauge tables, wherein a cofferdam is reclaimed along the consolidation area border in the soft soil foundation, a soft soil consolidation layer is formed in the cofferdam, the soft soil consolidation layer is provided with the soft soil consolidation layer vacuum pipe network and a hydraulic fill consolidation layer, the hydraulic fill consolidation layer is provided with a bearing separation layer and the hydraulic fill consolidation layer vacuum pipe network, and the hydraulic fill consolidation layer vacuum pipe network is hydraulically filled with a sealing layer. The invention has the advantages of reasonable structure, convenient construction, short construction period, low cost, good consolidation effect, facilitation of construction in large areas, consolidation of the soft soil foundation, dredging, and reutilization of the dredged sludge after consolidation, and can solve the problem of difficult land occupation of a blow-off field and create economic benefits.

The invention discloses a construction method for a vacuum combined preloading consolidated foundation, and belongs to the field of building construction. The construction method is characterized by comprising the steps of (1) laying a sand mat; (2) constructing a plastic drainage plate; (3) arranging a drainage filtering water pipe, and constructing a vacuum pumping device and a sealing system; (4) conducting vacuum combined preloading; (5) conducting field observation and instrument embedment. According to the construction method for the vacuum combined preloading consolidated foundation, the reinforcement effect on a soft soil foundation is obvious, soil body solidification can be accelerated, the soil body status is improved, post-construction settlement of a building is reduced, and the novel foundation treatment method is expected to be widely used in construction for hydraulic works.

The invention discloses an extruding and extending device for horizontal loading drainage solidifying soft soil reinforcement and a construction method thereof, and belongs to the technical field of civil engineering. The extruding and extending device is formed by connecting a plurality of extruding and extending device units, wherein each unit consists of a central screw, a central nut pair, supporting rod pairs, a supporting beam and a water-permeable filter membrane; the central screw is formed by connecting a forward screw and a reverse screw; a forward nut and a reverse nut in the central nut pair are sleeved on the forward screw and the reverse screw respectively; the forward and reverse nut pair is hinged with a plurality of supporting rod pairs; the other end of each supporting rod pair is hinged to the supporting beam; and the water-permeable filter membrane is coated outside the supporting beam. The central screw of the extruding and extending device in a contraction state in soil is rotated to make the forward nut and the reverse nut move in opposite directions, the supporting rod pairs push the supporting beam and the water-permeable filter membrane to extend and extrude a soil body, and water in the soil is discharged to the extruding and extending device through the water-permeable filter membrane, so that the soil body is solidified; and the water in extruding and extending holes is drained, and an appropriate material is injected, so that construction is finished. By the extruding and extending device and the construction method thereof, the soil body is quickly solidified, and settlement after construction is reduced.

The invention discloses a method for filling deep soft foundation zero additional load bubble mixed lightweight soil subgrade, which comprises the following steps: according to the load generated by the bubble mixed lightweight soil subgrade and a pavement structure layer, the foundation soil with 1.1-1.3 times of weight of the load can be excavated; a cushion layer is filled on a bottom layer; a base is made at the two sides of the subgrade and a baffle plate is constructed, a waterproof geotextile is paved in the deep scope of a foundation trench; the bubble mixed lightweight soil is casted on the cushion layer and the pavement is paved on the bubble mixed lightweight soil. By using the technical scheme of the present invention, the settlement of the subgrade can be reduced, and the additional stress of the foundation under the subgrade is zero.

The invention discloses a bottom-grouting-enlarged small-diameter prestressed tubular pile composite foundation construction method for processing a small-area / narrow-range deep mucky soil or soft clay foundation, which is characterized in that: by utilizing the high bearing capacity and pile-bottom concrete reinforced and enlarged ends of bottom-grouting-enlarged small-diameter prestressed tubular piles, the bottom-grouting-enlarged small-diameter prestressed tubular piles effectively reduce diameters of pile bodies of the conventional prestressed tubular piles, reduce the buried depths of the pile bodies, and are arranged in a plane at a proper pile spacing to achieve micro shallow and dense pile group effect and achieve shallow soft field soil composite foundation reinforcement effect. The method has the advantages that: on bottom-grouting-enlarged small-diameter prestressed tubular pile composite foundation, the small-diameter prestressed tubular piles are used to compact the surrounding soil to transfer load, and grouting and reinforcement of pile bottoms are performed to improve the end bearing capacity, so that a shallow pile-based composite foundation is formed. Compared with a normal large-area soft soil foundation composite foundation processing method and a prestressed tubular pile foundation method, the method has the characteristics of simple process, high construction speed, miniature construction equipment, material saving and low cost.

The invention discloses a retaining and protecting method for a vacuum preloading foundation excavation at a soft soil road section, which is used for vacuum preloading for the soft soil road section when in the retaining and protecting for the foundation excavation in the underpass construction of the soft soil road section. In the method, firstly, cement mixing piles are piled at the corresponding positions of the ground level road at the two sides of an underpass section and are used for enclosing and dividing the soft soil road section into a plurality of closed regions, plastic drainage boards are piled in each closed region at a certain interval, a sand cushion is laid at the ground of the closed region and is internally embedded with a strainer, and the sand cushion is covered by a sealing film to be isolated from atmosphere; then, a vacuum pump is communicated with the strainers in the sand cushion and exhausts the air in the sealing film; finally, the vacuum degree in the sealing film can be kept to be more than 80KPa; the degree of consolidation of the foundation is more than 80% when stopping the preloading for the underpass section, then the foundation excavation is excavated by the underpass section, and a retaining wall of the underpass section is arranged.

The invention relates to a highway-foundation construction method and particularly relates to a construction method for combining composite foundations of rigid piles and soft-soil foundations of water-draining consolidation and reinforcement highways. The construction method comprises the construction steps of paving a working cushion layer; adopting a bagged sand well as a vertical water-draining body, adopting vibratory tube sinking to lower the bagged sand well, carrying out vibratory tube pulling, and supplementing materials at an empty well section in the tube pulling process; driving rigid piles, carrying out vibratory tube pulling after filling up concrete into sleeves by a mode of vibratory tube sinking, wherein the tube pulling speed is less than 1.2m / minute, and the tubes cannot be inserted inversely in the process of vibratory tube pulling; and casting pile caps, and adopting an inverse excavation construction method to cast the pile caps in constructed working cushion layers or filled soil; and backfilling roadbeds, arranging a settlement plate on column tops and among columns, filling to the height of less than 5m and adopting a vibratory pressing machine for flattening. Compared with the construction method for composite foundations of pile supporting dikes and rigid piles, the construction method for combining the composite foundations of the rigid piles and the soft-soil foundations of the water-draining consolidation and reinforcement highways has the advantage that the cost can be respectively saved by 40% and 46%.

The invention discloses a foundation pit support method of soft soil foundation. Vacuum preloading is carried on soft soil road sections as the foundation pit support is carried on undercrossing construction of the soft soil highway. The construction steps are as follow: firstly, cement-soil mixing piles are erected at the corresponding positions on ground at two sides of the undercrossing road section and the soft soil road section is divided into a plurality of closed areas by the cement-soil mixing piles; plastic drainage plates are erected in a certain space in each closed area; sand cushion is paved on the ground in each closed area and a filter strainer is embedded in the sand cushion; the sand cushion is covered by a sealing film so as to be separated from air; a vacuum pump is communicated with the filter strainer in the sand cushion and exhausts to discharge air in the sealing film; finally, vacuum value in the sealing film is kept to be more than 80 KPa. As the preloading of undercrossing road section is stopped, the foundation degree of consolidation is required to be more than 80% and then foundation pits in the undercrossing road section are excavated and parapets in the undercrossing road section are set.

The invention discloses an embankment structure for reducing the generation rate of bump at a bridge head and a filling method. The embankment structure comprises an under layer, a stone layer, a bump-preventing layer and a buffer layer, which are sequentially arranged, wherein the bump-preventing layer comprises a plurality of bump-preventing units and fillers filled in the peripheries of the bump-preventing units and between the adjacent bump-preventing units; each bump-preventing unit comprises a pored pipe body of which the periphery is coated with geotechnical cloth, a geogrid for connecting a defined amount of pored pipe bodies together, and fillers filled in the peripheries of the pored pipe bodies. The filling method comprises the following steps: cleaning a field; laying the under layer of an embankment; laying a filler layer, and laying the geogrid on the filler layer; placing the pored pipe bodies coated with the geotechnical cloth on the geogrid; winding the geogrid on the defined amount of pored pipe bodies according to a certain spacing; repeating the step 5 for multiple times, and then filling soil and stone to be used as the buffer layer; and compacting. The embankment structure has the advantages of simplicity and convenience in construction, low cost, high economic benefit, good drainage condition, environmental friendliness, conservation and the like.

The invention discloses a stirring pile-permeable concrete pile compound foundation, which comprises a plurality of rows of stirring piles and permeable concrete piles, wherein the stirring piles and the permeable concrete piles are arranged in a row spacing way; and a gravel cushion layer is paved on the surface of the foundation on the upper parts of the stirring piles and the permeable concrete piles. The invention discloses a method for treating the foundation simultaneously. The compound foundation has high bearing capability and high permeability, post-construction settlement can be effectively reduced, and the liquefaction resistance of the foundation can be improved. Meanwhile, under the action of drainage consolidation, the compound foundation can be used for eliminating engineering diseases caused by stirring pile construction.

The invention relates to a construction method of a bagged rammed small-diameter soil-cement pile composite foundation in a small-area weak and deep soft soil layer. The construction method is characterized in that a small-diameter soil engineering pipe bag is combined with the traditional soil-cement pile processing method to extrude surrounding soil bodies to be dense in a limiting way by utilizing the gluing reinforcement of cement and the restraint action of the soil engineering pipe bag so as to form high-density minitype pile group effect and enhance the bearing capability of the foundation. The diameter of the traditional soil-cement pile and the loss of soil-cement in the foundation are reduced by utilizing the packaging and restricting action of the soil engineering pipe bag, and the embedment depth of a pile body is reduced, thereby the reinforcement effect of a shallow-layer weak field soil composite foundation is achieved. Compared with construction method of the soil-cement pile large-area soft soil foundation, the invention has the advantages of simple process, fast construction, miniaturized construction equipment, material saving and low cost and can be popularized and used in the processing process of a small-area deep and weak field soil foundation.

The invention relates to a pilot shield tunnel which crosses a newly-built seawall and a ground treatment method. The pilot shield tunnel is formed by that a plurality of duct pieces are assembled by bolts in a circumferential mode; the corresponding positions of the duct pieces are preinstalled with consolidated filling injection ports and operating ports of a high-pressure jet grouting pile; a plurality of high-pressure jet grouting piles are arranged at a certain distance from the bottom part of the duct pieces and form a transition layer; a reinforcing layer is formed by the consolidated filling injection in the sludge of the pilot shield tunnel which is formed by the duct pieces; the ground treatment method comprises: a plastic draining board is adopted to carry out ground foundation; the corresponding positions of the duct pieces are preinstalled with consolidated filling injection ports and operating ports of the high-pressure jet grouting pile; when the pilot shield tunnel crosses at the lower part of the foundation of the seawall, the construction of high-pressure jet grouting pile is carried out in the soft soil of a lower horizontal layer of the tunnel through the operating ports of the high-pressure jet grouting pile; the bottom of the high-pressure jet grouting pile enters a holding layer; after the construction of the high-pressure jet grouting pile is completed, consolidated filling injection is adopted at the periphery of the shield tunnel, thus having the characteristics of effectively reducing after-construction settlement of the shield tunnel which encounters the lower horizontal layer of the deep soft soil when crossing the newly-built seawall so as to prevent the tunnel from being tension fracture in the lengthways direction and further have influence of taking and draining water, and effectively improving the transverse forced state of the shield tunnel so as to prevent damage caused by the concentrated force on a single duct piece.

The invention discloses a soft soil stratum in-situ curing agent preparing and feeding equipment and curing process thereof, the soft soil stratum in-situ curing agent preparing and feeding equipment comprises an excavator and curing agent preparing equipment, a material conveying pipe is arranged between the excavator and the curing agent preparing equipment, the curing agent preparing equipment is provided with an automatic quantitative feeding system, the excavator is provided with a bucket arm, the tail end of the bucket arm is connected with a powerful stirring head, and the curing agent preparation equipment comprises a storage tank, a pressure chamber and an air compressor. The soft soil stratum in-situ curing agent preparing and feeding equipment and the curing process thereof replace a traditional replacement filling method for treating the soft soil stratum, zero discharge of engineering waste soil can be achieved, the influence degree of transportation and the waste soil on the environment is reduced, a large number of replacement materials do not need to be used, the use amount of gravel is reduced, and mountain cutting quarrying and river channel sand digging are reduced; the influence on surrounding buildings is reduced, the construction speed is increased, a hard shell layer can be quickly formed, cyclic utilization of resources is achieved, and energy conservation and environmental protection are achieved.

The invention relates to a soft foundation fast separating and punning method, which comprises the following technical steps: step 1, water and gas separating integral tube well layout; step 2, water and soil separating and water descending; step 3, water and gas separating construction after dynamic reinforcement; step 4, tube well backfilling. The soft foundation fast separating and punning method has the advantages that water and gas separating tube well water descending is combined with a dynamic reinforcement method, the requirement on water descending depth is met, pore water pressure generated after dynamic reinforcement can also be rapidly dispersed, and the soft foundation fast separating and punning method is applicable to the requirement of dynamic reinforcement of low-permeability soil.

The invention discloses a construction method for treating an adjacent existing railway line soft soil foundation and a roadbed structure thereof. The construction method comprises the steps of leveling the site, and longitudinally constructing a plurality of rows of rigid CFG piles along the line in the slope toe area of the side, away from an existing railway line, from a safety limit part to a designed newly-built roadbed; longitudinally constructing a plurality of rows of flexible jet grouting piles along the line in the slope toe area of the side, close to the existing railway line, from the safety limit part to the designed newly-built roadbed; longitudinally paving a mattress layer along the railway line above the rigid CFG piles and the flexible jet grouting piles and at the top of a soft soil layer; and paving a roadbed above the mattress layer according to the design. According to the construction method and the roadbed structure, the roadbed bearing capacity is effectively improved, the post-construction settlement of the roadbed is reduced, the stability of the soft soil foundation is guaranteed, and the negative impact to the safe operation of the existing railway line is avoided; and the roadbed reinforcement structure is simple in form, good in stratum adaptability, reasonable in technology, and economic in cost, and has relatively high popularization and application value.

The invention relates to an integrally-arranged and externally-wrapped double-layered water discharging body and middle concrete combined pile which is formed by a pile body inner side annular water discharging body, a cast-in-place concrete thin-walled pipe pile body, a pile body outer side annular water discharging body, a prefabricated pile tip and a prefabricated reinforced concrete cover plate; the prefabricated pile tip is arranged at the bottom of the combined pile; the top face of the pile tip is provided with four annular grooves for limiting the position of an immersed tube; the prefabricated reinforced concrete cover plate is arranged at the top of the combined pile; and a water discharging branch pipe is arranged inside the cover plate. According to the integrally-arranged and externally-wrapped double-layered water discharging body and middle concrete combined pile disclosed by the invention, the water discharging bodies with the uniform thickness are arranged on the inner side and the outer side of a concrete tubular pile, so that the consolidation of the soil body between the piles can be accelerated, the bearing capability of a soil foundation is improved, diseases of pile breaking and the like, caused by a soil squeezing effect, can be prevented when an adjacent pile is pegged, and the good technical economic benefit can be realized. The invention further provides a construction method of the combined pile.

The invention discloses a top-down rigid pile compound foundation construction method which comprises the following construction procedures: performing roadbed treatment at the bottom of a whole compound foundation, performing embankment filling at the upper part of a roadbed after the roadbed is flattened, performing rigid pile construction after embankment filling is finished, and finally constructing a structural layer at the uppermost layer above an embankment to form a structural layer-rigid pile-embankment-roadbed common action system. By virtue of top-down construction, the aims of lowering the manufacturing cost, shortening the working period and controlling the settlement are fulfilled by changing the construction sequence of the rigid pile compound foundation in a road project and fully using the compaction action of the embankment on a soft roadbed, the extrusion action of the rigid pile and a dynamic rigid pile driving process on the embankment and the jacking and hooping action of a working process on the embankment according to stress characteristics of the roadbed and the rigid pile; the construction is easy and convenient, and the controllability is high; the top-down rigid pile compound foundation construction method is suitable for general soft roadbed treatment, and is particularly suitable for road-bridge transitional section treatment of a road.

The invention discloses a discrete pile-water permeability concrete pile novel binary composite foundation, which comprises concrete piles and water permeability concrete piles, wherein the concrete piles and the water permeability concrete piles are alternately arranged in rows, and the foundation surfaces of the upper parts of the concrete piles and the water permeability concrete piles are provided with broken stone hardcores. The invention also discloses a treatment method of the composite foundation. The composite foundation belongs to a binary foundation treatment mode integrating high bearing performance and high water discharge performance, the post-construction settlement of the foundation can be reduced, and in addition, the liquefaction resistance capability of the foundation can be effectively improved. In addition, during the concrete pile construction, hyperstatic pore water pressure can be generated in the foundation, the ground surface doming (cohesive soil layers) and the pile settlement (sandy soil layers) can be caused, and the occurrence of engineering harm can be prevented through reducing hyperstatic pore water pressure during the concrete pile construction via the arrangement of the water permeability concrete piles.