784 results about "Foundation engineering" patented technology

The invention provides a rotary-digging combined pile-forming construction method in complicated geological conditions. The method comprising the following steps of: firstly, positioning a pile foundation; secondly, positioning a steel protecting barrel; thirdly, sinking the steel protecting barrel; fourthly, when the steel protecting barrel penetrates through a boulder layer without encountering the boulder, sinking the steel protecting barrel to the design elevation by using a vibration hammer; fifthly, starting a rotary digging and drilling machine to perform rotary digging and drilling at the inner side of the steel protecting barrel; sixthly, hoisting an impacting and catching hammer by a hoist, and downwards hammering and impacting the boulder by the impacting and catching hammer; seventhly, starting the rotary digging and drilling machine to continuously perform rotary digging and drilling to the design elevation; eighthly, fishing slag from the bottom of a hole; ninthly, checking and accepting a final hole; tenthly, aligning the skeleton of a steel reinforcement cage to the opening of the hole and slowly hoisting into the hole by the hoist; eleventhly, secondly cleaning the bottom; twelfthly, concreting; and thirteenthly, after primarily setting the concrete, lifting up the steel protecting barrel by the hoist. The method has the advantages of high safety and reliability, strong stratum adaptability and high construction progress and is suitable for the pile foundation engineering in cities with complicated geological conditions.

The invention discloses a calcareous sand dynamic-static load multi-functional pile foundation model test device and relates to a model test technology for pile foundation engineering. The structure of the device is as follows: a hydraulic lifting unit is arranged at the bottom of the whole bracket, a model box is arranged on the hydraulic lifting unit, the model box is filled with calcareous sand, and a model pile is arranged in the calcareous sand; a water level fluctuation system is connected with the model box; the fixed ends of a vertical load applying part, a horizontal load applying part, a hydraulic loading part and a pneumatic loading part are separately arranged on the whole bracket, and the movable ends of the vertical load applying part, the horizontal load applying part, the hydraulic loading part and the pneumatic loading part are separately connected with the model pile; and an induction acquisition system is separately connected with the model pile and the model box. The device can apply various types of load on the model pile and particularly can simulate applying various complicated loads in a marine dynamic environment and obtain parameters related to the pile and earth interaction process of the model pile under complicated load action.

The invention discloses a scraping-cutting and impacting combined type drill which belongs to the field of rock breaking tools for drilling equipment in petroleum and gas, mine engineering, building foundation engineering construction, geology, hydrology and the like. The scraping-cutting and impacting combined type drill comprises a drill body and a fixed cutting structure solidified on the drill body, wherein the drill body is also provided with an impacting-cutting structure; the impacting-cutting structure comprises a force transferring mechanism for transferring impact force, and impacting-cutting teeth; the impacting-cutting teeth are solidified on a punch at the tail end of the force transferring mechanism; and the punch can slide or do sliding impact relative to the drill body in the impact force transferring direction. Compared with the conventional PDC (Polycrystalline Diamond Compact) drill, the scraping-cutting and impacting combined type drill is beneficial to the drilling into stratum of the cutting teeth, improving the rock breaking efficiency and slowing the abrasion of the cutting teeth; and especially, the scraping-cutting and impacting combined type drill has obvious technology advantages when being used for drilling the high-strength and strong-abrasiveness strata difficult to drill.

The invention relates to a method for dynamic risk assessment and management of foundation pit engineering, comprising the following steps: 1) using Delphi method to identify risk factors of foundation pit engineering and classifying them; 2) according to the risk occurrence probability, risk loss and risk controllability of foundation pit engineering 3) Using the improved hierarchical method based on triangular fuzzy numbers and the fuzzy comprehensive evaluation method to evaluate the risk of foundation pit engineering; 4) According to the risk evaluation results, put forward risk response decisions; 5) The risk of foundation pit engineering is tracked and monitored. If there is a new risk source, return to step 1), and carry out risk identification, risk estimation, risk evaluation, risk decision-making and risk tracking again; if there is no new risk source, the risk management process ends. The invention overcomes the disadvantage that the static risk assessment does not consider that the risk factors change with the development of the project construction, and the risk assessment index and classification standard are more systematic and comprehensive, and the risk assessment model is more accurate and reasonable.

The invention discloses a crossed scraping-impacting composite drill bit belonging to the field of rock blasting tools for drilling equipment for oil and gas, mine engineering and building foundation engineering construction, geology, hydrology and the like. The crossed scraping-impacting composite drill bit comprises a drill bit body, a fixed cutting structure, a disc cutter cutting structure and a hydraulic structure, wherein the fixed cutting structure, the disc cutter cutting structure and the hydraulic structure are arranged on the drill bit body; the drill bit body is also provided with an impact cutting structure; and the impact cutting structure comprises a force transferring mechanism for transferring impact forces and impact cutting teeth, wherein the impact cutting teeth are solidified on a punch arranged at the tail end of the force transferring mechanism, and the punch can slide or slidingly impact relative to the drill bit body in the impact force transferring direction. Compared with a drill bit for blasting a rock in a cutting way, the crossed scraping-impacting composite drill bit is not only beneficial to the drilling of the cutting teeth of the drill bit to stratums and the increment of the rock blasting efficiency, but also beneficial to the retardance of the wear rate of the cutting teeth and particularly has remarkable technical advantages for higher-strength and stronger-abrasiveness stratums which are difficult to drill.

Disclosed is a preparation method of shock-proof ecological concrete, belonging to the concrete material field. Aiming at the defect of poor shock resistance of common concrete, the preparation method firstly adopts rubber and a cement stone matrix interface modifier to pre-treat rubber aggregates, then mixes and agitates materials such as cement, coarse and fine aggregates, rubber aggregates, water and admixture in a certain proportion evenly, and prepares the concrete after the curing for a certain period of time. The concrete has compositions per cubic meter, in proportion: cement: 350 to 500kg / m<3>; water: 150 to 250kg / m<3>; fine aggregates: 200 to 650kg / m<3>; coarse aggregates: 1000 to 1200kg / m<3>; high-efficient water-reducing agent: 0 to 8kg / m<3>; interface modifier: 1.8 to 6kg / m<3>; and rubber aggregates: 50 to 200kg / m<3>. Compared with the common concrete and common rubber aggregate concrete, the concrete in the invention has advantages of obviously improved shock resistance and excellent concrete workability, and can be widely used for various impact load-bearing structures such as foundation engineering as well as roadbeds and sleepers of trains, and has broad promotion and application prospect.

The invention discloses a bored composite pile structure under karst cave / soil cave geological conditions and belongs to the technical field of construction pile foundation engineering. The bored composite pile structure is composed of a borehole, a preformed pile, a protective cage, clay cement grout, a grouting pipe, karst cave (soil cave), protective cage longitudinal bars, protective cage hooping and geotechnical cloths. Constructions of a cast-in-situ bored pile under the karst cave / soil cave geological conditions are usually encountered with greater difficulties, and therefore the preformed pile can be implanted by way of drilling, and then the gap between the preformed pile and the borehole is filled with clay cement grout. Namely, first, a hole is drilled at a design pile position, and meanwhile the protective cage is fixed at a corresponding position, according to the height of a karst cave (soil cave) burial depth below the pile position, of the preformed pile, the protective cage is composed of the multiple protective cage longitudinal bars, the cage hooping located on the periphery of the protective cage longitudinal bars and taking a shape of a ring and the geotechnical cloths located on the periphery of the hooping; then, the preformed pile is lifted and placed into the borehole and the center of the preformed pile and the center of the borehole are ensured to coincide; finally, the clay cement grout is poured into the gap between the pile and the borehole through the grouting pipe and after the clay cement grout solidifies and stabilizes, the bored composite pile is formed.

The invention discloses a cast-in place pile post-grouting construction method for pouring construction. The method comprises the steps that cast-in place pile pore-forming construction is carried out; first-time hole clearing is carried out; reinforcement cage and grouting pipe mounting is carried out; second-time hole clearing is carried out; pile body concrete placing is carried out; pile concrete curing is carried out; grouting soil mass reinforcement is carried out; grouting is stopped; next cast-in place pile grouting working is carried out; and checking and accepting are carried out. After pile forming, the intensity of pile body concrete reaches a certain degree, a high-pressure generating device is used, high-pressure cement grout flow with concentrated energy is formed, grout is combined with pile body surrounding soil mass through the effects of permeating, separation, filling, compaction and the like, pile body sediment and pile side mud cakes are solidified, pile side friction resistance and pile end bearing force are enlarged, the shortcomings that due to hole bottom sediment and pile side mud cakes of a common cast-in place pile, bearing force is low, and vertical load decreasing is high are overcome, and important economic and social significance is achieved in single pile bearing force improving, pile foundation sedimentation lowering, pile foundation engineering quality guaranteeing and the like.

The present invention relates to a rock anchor foundation structure suitable for a mountain photovoltaic module and a construction method of the rock anchor foundation structure. A technical solution of the present invention is as follows: the rock anchor foundation structure comprises a drill hole drilled in a rock slope, an anchor rod module arranged in the drill hole and a photovoltaic power station module. The photovoltaic power station module is connected with the anchor rod module through a hollow connecting steel pipe; the photovoltaic power station module comprises a bracket welded on the top of the hollow connecting steel pipe, a beam mutually hinged with the top of the bracket and a photovoltaic cell panel arranged at the upper part of the beam. The rock anchor foundation structure of the present invention is suitable for the technical fields of around treatment and foundation engineering design.

The invention relates to a drilling pile with a bar-reinforced squeezing branch-plate. The pile comprises a precast pile tip, a uniform-section pile body and a branch-plate body; the uniform-section pile body is composed of a longitudinal main bar and spiral bars; the precast pile tip is placed at the end of the uniform-section pile body; the branch-plate body is positioned on the outer wall of the uniform-section pile body, and comprises a branch-plate upward-oblique bar and a branch-plate downward-oblique bar which are connected up at a certain angle. The invention solves the problem of laying bars in the branch-plate body, ensures the shape and stability of a drilled hole wall and the reamed hole wall of the branch-plate body, and solves the quality problem of soil-in-concrete by an elastic membrane, because alternating the operations of pulling out the elastic membrane and pouring the pile can avoid the adverse effect of the left elastic membrane to the pile side friction force. The invention belongs to the pile foundation engineering field, can be applied to the construction of cast-in-place pile with a squeezing expansion branch-plate, also has good applicability in the soil layers where the common methods are limited such as weak soil and sand, and can achieve good technical and economical effects.

The invention discloses a circular buckle plate mechanical pile splicing method for precast square piles. An end plate with a circular groove and an end plate with a circular protruding plate are spliced and are fixed at the two ends of two precast square piles to be butted respectively. First grooves are formed in the splicing position between the end plate with the circular protruding plate and the end plate with the circular groove, second grooves are formed in the splicing position between the end plate with the circular groove and the end plate with the circular protruding plate, and the first grooves and the second grooves are formed in a joint circle of the end plate with the circular groove and the end plate with the circular protruding plate. The end plate with the circular protruding plate and the end plate with the circular groove are spliced through connection accessories. According to the method, mechanical connection points can be reduced relatively, the connection reliability is improved, the foundation engineering potential safety hazard is reduced, and the building safety is further guaranteed.

The invention relates to an auxiliary device used in underwater concreting in pile foundation engineering and in particularly relates to an underwater concreting sampler of a bored pile for carrying out sampling testing on an underwater concreting state. The underwater concreting sampler of the bored pile comprises a section of hanger rope, the lower end of the hanger rope is connected with a hanging beam, two arms of the hanging beam are connected with the cylinder wall at the upper end of a storage cylinder in a shape of a cylinder, an openable or closable valve is arranged at the bottom of the storage cylinder, the valve consists of two semi-circular door plates, a rotary shaft arranged on the diameter is arranged at the opening at the bottom of the storage cylinder, the two semi-circular door plates are both articulated to the rotary shaft, a stop pin is also arranged on the inner wall at the lower end of the storage cylinder, and the edges of the semi-circular door plates drop on the stop pin when the valve is closed. The underwater concreting sampler of the bored pile has a simple structure, is easy to process, is low in manufacture cost and is convenient to use; and with the adoption of the underwater concreting sampler of the bored pile, during construction, the storage cylinder is put into a pouring hole through the hanger rope, whether pouring is in place is simply judged by a sampling result of the storage cylinder without deep influence by a pile foundation, and the accurate position on the top surface of concrete can be exactly and intuitionally judged, so that quality accidents generated in pile foundation construction are avoided.

The invention discloses an FRP pipe and thick-wall steel pipe compounding hollow recycled concrete pile which is mainly formed by an FRP pipe, a round reinforcement cage framework, a thick-wall steel pipe and recycled concrete. The round reinforcement cage framework and the thick-wall steel pipe are arranged in the FRP pipe, and the round reinforcement cage framework, the thick-wall steel pipe and the FRP pipe are arranged concentrically. The recycled concrete is poured in annular space between the FRP pipe and the thick-wall steel pipe. The bearing capacity and deformation resisting capacity of the single pile can be greatly improved through the built-in thick-wall steel pipe. The wrapping FRP pipe can effectively prevent a pile body from being corroded, and the durability of the pile body is improved. Meanwhile, the FRP pipe and spiral stirrups are combined to restrain the inner recycled concrete, and the bearing force of the compounding pile is further improved. Waste concrete is fully utilized as recycled aggregate, and application and popularization of the recycled concrete in building foundation engineering are facilitated. In a word, the compounding hollow recycled concrete pile has the advantages of being good in pile forming quality, high in bearing force, good in deformation resisting capacity and durability, small in influence on the environment, high in construction speed and the like.

The invention relates to a single-pile vertical circulation loading test device and method for simulating high-speed railway loads. The device comprises a test chamber, a test pile, a counter-force frame, an upper rigid beam, a fixing rod and an upper loading unit, wherein the test chamber is a square steel frame, and the main component of the upper loading unit is an electric vibration exciter, and the electric vibration exciter is suspended above the test box by using the upper rigid beam. The power amplitude, the loading frequency, the loading waveform and the like of the exciter are controlled by a signal controller; a displacement sensor is arranged at the top of the test pile, and a resistance strain gauge is arranged in the pile body direction. The device can simulate the working condition of the vibration load on a foundation of a pile foundation, the vibration amplitude and the vibration frequency of the dynamic load can be adjusted, and the stress and displacement applied tothe pile top and the pile body stress distribution can be measured and automatically recorded; the device is simple in structure and can realize system research on single-pile bearing capacity and deformation characteristics under the action of a long-term vertical circulation load, and has important significance in calculation of the pile foundation bearing capacity and deformation in the pile foundation engineering design.

The invention relates to a precast expanding pile as well as a construction method and construction mechanical equipment thereof in the field of pile foundation engineering. The construction method of the precast expanding pile of the invention comprises the following steps of: sedimentating a hollow precast pile (2) into a preset depth, wherein the bottom of the hollow precast pile (2) is connected with a pile plug (1); moving away the pile plug (1) and pouring an immature pile body material into the hollow precast pile (2); squeezing the immature pile body material into a soil body at the lower part of the hollow precast pile (2) to form a pile bottom expanding segment (4); and repeating the steps until the pile bottom expanding segment (4) satisfies the requirement. The precast expanding pile obtained through the construction comprises the hollow precast pile (2) at the upper part, the pile bottom expanding segment (4) at the lower part and the pile plug (1) at the bottom, and high-efficiency construction equipment is developed, the pile in the form is convenient to construct, has reliable quality, greatly improves the bearing capacity of the end parts of the precast piles, such as PHC (Prestress High Cement ) tubular pile, hollow square piles, and the like which are widely applied at present and can be used as an pulling and compression resistant bearing pile with high bearing capacity and low manufacture cost.

The invention discloses a demonstration and display teaching device for a soil engineering centrifugal simulation technology test. A centrifuge testing demonstration part is arranged on the right side of a whole display table. A computer, a display screen, a direct current power supply, a control panel, an operation room model, an electric control cabinet model and an operation table model are arranged on the left side of the display table. The demonstration and display teaching device can be used to demonstrate rock-soil body deformation and damage processes to non-professional people or students, enables the non-professional people or the students to understand basic characteristics of soil, can be combined with soil mechanics and foundation engineering courses to conduct test teaching, achieves efficient studying effect through active participation of the students, and can be directly used for research result introduction, class teaching, and the like when connected with an external display device through a computer. The demonstration and display teaching device is complete in function, simple, visual, convenient to operate, and capable of meeting requirements of rock-soil type test demonstration and displaying teaching.

The invention relates to a foundation pit flexible support active earth pressure calculating method considering action point position. The method overcomes the shortcomings of a coulomb earth pressure calculating method and a rankine earth pressure calculating method. The method includes the following steps: determining accuracy control quantity eps, foundation pit geometric elements and earth body physical dynamic parameters; determining the position coefficient na of the active earth pressure resultant force action point; utilizing the curve y=s(x) to represent the earth body slip surface; determining the minimum value phi min of the function phi (x0,s0) to judge whether phi min is smaller than or equal to eps; finally calculating the resultant force of the slip surface equation and the active earth pressure. The foundation pit flexible support active earth pressure calculating method is line with reality, high in reliability and favorable for reasonable design and scientific management of pit foundation engineering.

The invention belongs to the field of foundation engineering and relates to equipment and method for improving a bearing capacity of a cast-in-place pile under a soft soil foundation condition. The equipment comprises a cement paste pumping device, an injection grouting pipe position control device, am injection grouting pipe and a rotatable three-directional nozzle, wherein the injection grouting pipe is arranged on the injection grouting pipe position control device and the position of the injection grouting pipe in a pile hole of the cast-in-place pile through the injection grouting pipe position control device; the cement paste pumping device is connected with the rotatable three-directional nozzle through the injection grouting pipe; the rotatable three-directional nozzle is used for carrying out slurry spraying work on an injection grouting reinforcing region in the pile hole of the cast-in-place pile. The equipment and method for improving the bearing capacity of the cast-in-place pile under the soft soil foundation condition, provided by the invention, are simple in structure and are convenient to control and implement; soft soil at the periphery of a pile body is reinforced by adopting an injection grouting manner and the strength of a soil body is improved, so that the aims of guaranteeing the pile forming quality of the cast-in-place pile under the soft soil foundation condition and improving the friction resistance of a pile foundation side and a total bearing capability are realized.

The invention discloses a composite drill bit with a cutter blade provided with a cutter disk cutting structure, and belongs to the technical field of drilling equipment in petroleum and gas, mine engineering, building foundation engineering construction, geology, hydrology and the like. The composite drill bit with the cutter blade provided with the cutter disk cutting structure comprises a drill bit body, a fixed cutter blade and cutter disks. The drill bit body is provided with the fixed cutter blade, the fixed cutter blade is provided with fixed cutting teeth, and a range of a deflection angle alpha is 20 degrees <=|alpha|<= 90 degrees. The drill bit body is provided with at least one cutter disk cutting unit which is composed of the cutter disk, the cutter disk cutting teeth arranged on the cutter disk and a cutter disk shaft. The at least one cutter cutting unit is arranged on the fixed cutter blade. The cutter disk is connected with the fixed cutter blade in a rotating mode. Structural features of the cutter blade type drill bit are utilized sufficiently, and thus a geometry space of a drill bit cutting structure area is saved, combination property of the drill bit is improved.

The invention relates to a mechanical connection structure for splicing precast square piles. An end plate for butting is arranged at an end of a precast square pile to be butted. The mechanical connection structure is characterized in that: a screw hole is formed on a side surface of the end plate, mechanical connection plates are arranged on the side surfaces of the mutually butted end plates, and the mechanical connection plates are connected with the screw holes on the side surfaces of the end plates through bolts so that the butted end plates are fixedly connected. The connection structure can relatively reduce the mechanical connection points, improve the connection reliability, reduce the potential safety hazard of foundation engineering, further ensure the safety of a structure and simultaneously improve the convenience in construction.

The invention relates to super-thick large-volume foundation anti-cracking concrete which comprises the following components in proportion by weight: 235-330kg of portland slag cement, 735-791kg of sand, 1,032-1,186kg of graded coarse aggregate stone, 155-210kg of water, 45-90kg of coal ash and 3.76-14.8 kg of compound additive. The invention reduces super-thick large-volume foundation cracks, creates conditions for the construction of a next working procedure, fundamentally solves the problem of cracks of the concrete in the processes of hydrating, hardening and curing, improves the integrity, the stability and the safety of a super-thick large-volume foundation, improves the durability and the anti-cracking function of the concrete and prolongs the service life of equipment foundation engineering.

The invention discloses a diamond drill bit and belongs to the technical equipment field of petroleum and natural gas drilling engineering, mine engineering, building foundation engineering construction, geologic drilling, tunnel engineering, hydrology, non-excavation and the like. The diamond drill bit comprises a drill bit body and a plurality of blades extending from the drill bit body, wherein cutting elements are arranged on the blades, at least one annular blank belt surrounding the center of the drill bit body is arranged on the drill bit body, and the blades in the position of the annular blank belt are inwards concaved to form circumferentially through grooves. The cutting energy consumption of the drill bit can be reduced, the rock breaking efficiency can be improved, meanwhile, transverse vibration of the drill bit can be inhibited, impact failure of cutting teeth of the drill bit is effectively reduced, the anti-drift capability of the drill bit in directional drilling is enhanced, large-size rock chips can be produced, the geological logging quality is improved, and the underground stratum information analysis and judgement accuracy under the condition of real drilling is improved.

The invention provides a method for determining rigidity of spring supports for simulating stress conditions of an elastic foundation. The method includes steps: S1, uniformly distributing the spring supports under a base to realize simulation replacement of the elastic foundation, wherein each spring support is formed by springs; S2, subjecting the base to node division at equal intervals, adopting different pitches according to different part structures and stress conditions of the base, and determining each pitch and the corresponding spring as a unit; S3, determining a settlement value and a top load of the spring of each unit; S4, determining rigidity of the spring supports, wherein k is equal to p / s, k refers to rigidity of the spring supports, p refers to the top load of the spring supports, and s refers to the settlement values of the spring supports. The spring supports are adopted for simulation of base constraint performed by the elastic foundation, the problem of calculation of the structure is effectively solved, and a scientific analysis means is provided for reasonability of hydraulic structure foundation engineering design in engineering application.

The invention relates to a method of preparing the solidifying material which has high performance in controlling intensity and stabilizing size, and a process of using the material to solidify granular materials such as common soil mass, weathered gravel, standard sand stone, industrial solid waste, tailing sand and sea sand to form indurations. The process comprises the following steps: (1) preparation of core materials; (2) preparation of the solidifying material which has high performance in controlling intensity and stabilizing size; (3) process of producing the solidifying material which has high performance in controlling intensity and stabilizing size; (4) application that the solidifying material which has high performance in controlling intensity and stabilizing size can be used to solidify granular materials such as common soil mass, weathered gravel, standard sand stone, industrial solid waste, tailing sand and sea sand in road projects, foundation engineering as well as water conservancy and hydropower projects, compared with traditional solidifying method, the process has the advantages that the intensity is controllable, the size is stable, the water resistance is dramatic and the construction is convenient with the general use amount ranging from 4% to 12%. As to the construction method, the construction technical process or specifications of soil lime and concrete can be referred to.

The invention discloses a disc cutter composite drill bit belonging to the field of rock blasting tools for drilling equipment for oil and gas, mine engineering and building foundation engineering construction, geology, hydrology and the like. The disc cutter composite drill bit comprises a drill bit body and a disc cutter cutting structure arranged on the drill bit body; the drill bit body is also provided with an impact cutting structure; and the impact cutting structure comprises a force transferring mechanism for transferring impact force and impact cutting teeth, wherein the impact cutting teeth are solidified on a punch arranged at the tail end of the force transferring mechanism, and the punch can slide or slidingly impact relative to the drill bit body in the impact force transferring direction. Compared with a drill bit (also named as wheel type drill bit) with the disc cutter cutting structure, the disc cutter composite drill bit is not only beneficial to the drilling of the cutting teeth of the drill bit to stratums and the increment of the rock blasting efficiency, but also beneficial to the retardance of the wear rate of the cutting teeth and particularly has remarkable technical advantages for higher-strength and stronger-abrasiveness stratums which are difficult to drill.

The invention relates to a T-type groove mechanical pile extension structure for a prefabricated square pile, wherein the end part of the prefabricated square column to be butted is provided with an end plate for butting; the structure is characterized in that a groove is arranged on the side surface of the end plate; the side surfaces of the end plates butted with each other are provided with trapezoidal clamp bodies; and the trapezoidal clamp bodies are meshed with the groove on the side surface of the end plate so that the butted end plates are fixedly connected with each other. The pile extension mode of the uplift resisting square pile provided by the invention adopts mechanical connection which can relatively reduce mechanical connections, improve connection reliability, reduce potential safety hazard of foundation engineering and further ensure the safety of buildings.

The invention discloses a construction method for constructing an underground garage through cover-excavation reverse construction, and is applied to the field of underground permanent structures andfoundation engineering in civil engineering. The construction method comprises the following steps that a temporary vertical enclosure structure, a temporary descending / stopping structure and a temporary vertical supporting structure are constructed at a ground elevation position, earthwork is excavated to a bottom elevation position of a top plate of the underground permanent structure, the top plate of the underground permanent structure is constructed, an entrance and exit for transporting the earthwork and materials are reserved in the top plate of the underground permanent structure, enclosure is sealed through a fence, other places except the entrance and exit are backfilled with surface layer covering soil, and ground or road restoration is carried out; earth excavation is carried out under the top plate through the entrance and exit, net hanging and spray protection are carried out on the surface of the temporary vertical enclosure structure, the underground permanent structureand a waterproof structure are constructed, and construction of the underground permanent structure and the waterproof structure of each layer is completed through circulation; and a parking system,a garage matching system and garage ancillary facilities are installed and debugged in the completed underground permanent structure.

A planetary hole-forming drill for the large-diameter piles in foundation engineering is composed of drilling frame, power shaft, gear set, drill rod and drill head. The said drilling frame consists of upper and lower supporting rings and oblique supporting rods through welding. The said gear set comprises a central gear fixed to power shaft and 3 planetary gears, 1-10 drill rods are fixed under each planetary gear via bearings and each drill rod has a drill head. It is suitable for the piles with 1-5 m of diameter.

The invention discloses a pre-stressed concrete pipe pile with skillful design and improvement on bearing capacity, which is of a cylindrical shape and the middle part of the pipe pile is hollow. The pre-stressed concrete pipe pile comprises a pipe wall and has the difference that the outer circumferential surface of the pipe wall is designed in a gear shape, the gear-shaped structure is decided by increasing coefficient of the surface area of the pipe pile, a numeric value of the gear-shaped structure is selected between 0 and 100 percent, even higher; the pre-stressed concrete pipe pile has the advantages that circularity of the outer circumference of the pipe wall of the concrete pipe pile is designed in the gear shape under the condition of the same diameter, length and soil, thereby effectively improving the surface area K of the pipe pile, effectively improving the bearing capacity P of the pipe pile, and reserving basic attribute circularity of the pipe pile simultaneously so as to allow the structure of the pipe pile to be more scientific and more conform to mechanical principle; and the product can be widely applicable to the pile foundation engineering of various architectures.