370 results about "Quicksand" patented technology

The invention discloses a construction method for a large ultra-deep well. In the method, the well is constructed by a drainage method of combining a waterproof curtain and deep well point dewatering; the well is manufactured and sunk; when the well is sunk to a preset depth, the well is constructed by a no drainage method; and when the well is sunk in place, concrete is used for sealing a bottom underwater. The method is characterized by comprising the following construction steps: a, constructing the waterproof curtain by using a rotary jet grouting pile; b, performing deep well point dewatering construction; c, prefabricating the well by sections; d, sinking the well by using the drainage method; e, sinking the well by using the no drainage method; and f, sealing the bottom by using the concrete underwater. The construction method for the large ultra-deep well has the advantages that: the construction steps are designed scientifically and reasonably, the construction period is shortened, piping and quicksand are avoided, the safety of surrounding buildings is ensured, and the construction cost of a project is saved.

The present invention relates to a new-type cement soil pile and its construction method. Said invention uses forced type or drum type stirring machine to stir cement, selected high-quality soil and additive or the ground surface, and adopts hollow long spiral drill to form hole and adopts the mode of pumping stirred material into pipe to form pile so as to obtain the invented cement soil pile.

A method for controlling the flowing sand of desert by the combination of alga with bacterium includes proportionally mixing the eremophytic algae powder with Bacillus edaphicus powder, proportionally inoculating the mixture in the flowing sand of desert while sprinkling nutrients conditioning liquid, and covering by ground film.

The invention relates to a large-section water-rich saturated fine sand railway tunnel excavation method. The method includes the following steps that firstly, pilot tunnels of double side walls are constructed in the lower half section of a positive hole of a tunnel in advance and are excavated with sub-steps, temporary inverted arches are arranged on the pilot tunnels respectively, rings are formed in a sealed and segmented mode, and sub-steps are used for carrying out look-ahead dewatering and drainage on the pilot tunnels; secondly, a method that an arc pilot channel is used for reserving core earth is used for excavating the upper section of the positive hole of the tunnel, the core earth is used for stabilizing a tunnel face, arc excavation is performed in place at a time, the positive hole primary supporting steel frame is spliced in place at a time, the temporary inverted arches and a middle partition wall which are next to the tunnel face are constructed to make an upper portion supporting structure form a ring in a sealed mode, the sub-steps are manually cut to excavate the core earth, an overall positive hole primary supporting lagging jack structure is rapidly established, the inverted arches are cast and concrete filling can be carried out in time; thirdly, a result is analyzed according to monitoring measurement data, the inner side wall in the hole, the temporary inverted arches and the middle partition wall are detached in a segmented mode and a composite lining is constructed in time. By means of the method, the construction problem that the self stability of the fine sand is poor and the fine sand rapidly deteriorates when encountering water and surges outwards like quicksand is solved.

The invention discloses a dynamic water quicksand stratum reinforcement grouting diffusion rule visual simulation experimental device and method. The device comprises an experimental box, a hydraulic pressure control loading system, a vertical hydraulic loading mechanism and a lateral hydraulic loading mechanism, a double liquid chemical grouting system and a test system connected to a computer. The method adopts an engineering geomechanical experimental model with a coal measure stratum physical analog simulation material, a waterproof stratum and an aquifer of certain height filled in the experimental box, aquifer grouting and water-plugging reinforcement visual physical simulation test is carried out hermetically under the conditions of circulating dynamic water pressure and vertical and horizontal lateral stress to acquire or quantitatively describe and analyze the diffusion rule of double liquid chemical grout in the water-bearing sandstone layer or quicksand layer, thus realizing visual simulation experiment of the double liquid component chemical grouting and water-plugging process under a similar water burst or water inrush condition. The method can effectively recognize and reveal the slurry diffusion and consolidation characteristics under a mining dynamic water condition, determine rational grouting and water-plugging parameters, and evaluate the grouting effect.

The invention discloses an integrated tower solar thermal power generation unit employing quicksand to store and transfer heat, and a tower solar thermal power generation unit built by 'quicksand' instead of conduction oil, fused salt or gas and the like to transfer and store heat. The device adopts fluid characteristics of the 'quicksand', and has the characteristics of thermostability, zero pressure, small thermal resistance and low cost of the 'quicksand'; and superheated steam is generated by sensibile heat and high-temperature air carried by the quicksand when flowing through a vapor generator to push a steam turbine generator to generate electricity, therefore, the construction cost of a tower solar thermal power generation unit is reduced by integral design, and a technological base is established for final implementation of parity power generation. The device belongs to the technical field of solar thermal electric power generation.

The invention relates to a construction method for excavating a support body in a tunnel by crossing a quicksand stratum. The construction method comprises the following steps of arranging veneer plugboards on the outer side and the face of a steel frame of an arch, using advanced small guide pipes on the arch, and plugging boards on the outer sides of the small guide pipes; plugging boards on the face, arranging guide pipes at the periphery of core soil, welding steel bars, close to the face, on the advanced small guide pipes of the arch and the guide pipes of the core soil, ensuring that intervals of the steel bars are suitable to blocking of veneers, paving the plugboards on the surrounding rock face, preserving the core soil and taking other related measures; in the excavation engineering, dividing the tunnel face into an upper step, a middle step and a lower step, ensuring that the excavation and support of each part are staggered along the longitudinal direction of the tunnel and are carried out in parallel, and quickly constructing a support system structure. The construction method can effectively prevent the risk of quicksand in a sand layer, and the construction safety is high.

A biologic method for immobilizing shifting sand and repairing the deserted land includes choosing proper phycophyta, herbage, shrub and tree, designing spray irrigation system, interplanting them, large-scale culturing of phycophyta, and periodicall spray irrigation.

The invention discloses a high-permeability zone under-water-level elevator foundation pit open caisson moulding bed construction method. The method includes the steps of foundation trench positioning and setting out, foundation pit bottom plate leveling, open caisson production and formation, open caisson sinking, open caisson bottom sealing, plain concrete backfilling of the periphery of the outer side of an open caisson, elevator shaft slope angle backfilling in the open caisson, and the like. By the method, slope setting amount of elevator shaft pit and catchpit soil excavation of construction is decreased, foundation soil disturbance is reduced, and foundation pit side wall brick moulding bed masonry and formwork pouring of a concrete cushion is replaced. Construction period is longer than that of normal construction, sand gushing and soil layer collapse are avoided in a foundation pit soil excavation process for special soil layer elevator shaft and catchpit construction, the problem that quicksand and collapse of the foundation pit wall are difficult to avoid under the circumstance of the underground water level with high-permeability coefficient is solved, and cost for quicksand and collapse management is saved by a large amount.

The invention discloses an integrated construction method for an artificial dug pile and a steel pipe concrete column. According to the method, a steel casing for avoiding quicksand in construction of the artificial dug pile is directly used for construction of the steel pipe concrete column of the upper structure; a mode of digging soil and sinking a steel pipe at the same time is adopted; in the process of sinking the steel pipe, after the previous section of steel pipe completely enters the soil layer, the second section of steel pipe is sleeved, and the operation is stopped after the design depth is dug; and the steel pipe sections are spirally connected by adopting male and female ports and fixed with the internal concrete through pins. A flange serving as a guard plate is welded at the contact position of a steel cylinder and a bottom plate, so that the contact area of the steel cylinder and the bottom plate is enlarged. By the method, the construction period can be shortened, the consumption of steel is reduced, the stability and the integrity of the structure are improved, the construction efficiency is improved, and the engineering cost is reduced.

The invention discloses a stripped live plant fence type sand-barrier protection system planting method, comprising the following steps: determining specific tasks and objectives of living sand-barrier protection; selecting living sand-barrier tree species; planting and designing before planting; firmly building and planting stripped sand; planting seedlings; using a living sand-barrier nursing method; and monitoring, supplementing, and improving functions. The method develops double sand-barrier protection advantages of high standing fences and plant sand-control through applying the technical scheme of living sand-barrier system combined design of specific blowing wind environment prevention regions and planting in real site. The method gives consideration on natural ecological restoration attribute of vegetation evolvement, and provides a novel ecological protective technology mode in which biological and mechanical measures are coordinated with each other. The method can satisfy the following protection functions: maintaining fragile water balance of inter-barrier natural sand, service life is more than 30 years, the sand-barrier protection system promotes quicksand to deposit in the prevention regions and overall sand surface is lifted, quicksand entry of a protected region is lower than 10% of sediment runoff of natural locality.

The invention relates to a covering film preventing sand and virescence method, which is that laying reentrant plastic covering film preventing sand in sand trough wall, fully burying sand in the covering film so that one end of the covering film, with 30-50kg force per square meter, is fixed in sand, setting several of cuts on the covering film, planting herb applied in sand or shrub with economic value in cuts. The covering film is not oxidized for 10-30 years and low cost. It not only prevents sand flowing in explicit sand zone but also sand winding in intrinsic sand zone and sand weather forming. It is the efficiency means that widely and drastically curing soil desertification and sand moving.

The invention relates to a novel working method for the manual advancing and restoration of a collapsed ultra-deep vertical shaft, which comprises the steps of advancing, installing templates, installing concrete reinforcing bars, pouring concrete, installing anchor rods, installing Mn steel protective canisters and pouring concrete. The method has the advantages of adopting the advancing proposal of the steel templates plus reinforced concrete lining plus the anchor rods plus the Mn steel protective canisters, integrating three in one, not only ensuring construction safety, but also having remarkable effects on construction schedule, being capable of applying successful experience to the project management to complicated rock mass similar to vertical shafts or faults, water-eroded caves, quicksand and the like, speeding up construction and reducing project investment; the technology is only at the development stage in China, shortens construction period greatly, raises the safety factor of workers in the well and ensures the construction quality of the vertical shaft.

The invention discloses a plant-machine compound type sand barrier design method, namely a method for promoting quick ecological restoration of a moving dune. The method mainly consists of technologies of laying a line transect, laying a grass grid sand barrier, planting a plant living sand barrier, directly seeding the plant living sand barrier and the like. The design principle is that the grass grid sand barrier is laid first to fix drift sand, meanwhile the plant living sand barrier is planted and directly seeded, the plant sand barrier can continue to play a windproof and sand-stabilizing function after a mechanical sand barrier loses efficacy, and the comprehensive sand stabilization effect is good. The method solves the difficult problems in the past that the governing difficulty of the tall moving dune in a high and cold area is large, the plant cover is hard to recover, and the drift sand is hard to stabilize, explores a new ecological restoration mode for preventing serious sandy desertification, and is a quick ecological restoration method for the moving dune in the high and cold area.

The invention relates to a basic construction process of a bridge in water, which comprises inserting steel plates on the periphery of a bearing cap base until the steel plates fold to form a cofferdam, arranging an inverted filter under the water in the cofferdam, arranging a vertical support of the steel structure, cyclically executing the following two steps until the water is pumped to the inverted filter, arranging the inner support of the steel structure, pumping water out from the cofferdam, and casting a concrete cushion after pumping water to the inverted filter. The scheme arranges the inverted filter in the cofferdam, guarantees the generation of quicksand in the process of pumping water under the situation that the bottom of the cofferdam is not be covered, simplifies the construction technology, makes the basic construction of the bridge which is carried out in the environment which is similar to dry land easy to be operated when casted the concrete cushion after pumping water, effectively shortens the construction period, saves the concrete for the back cover, and reduces construction cost, thereby realizing to provide construction environment for he bridge foundation in water such pier cap in safe, fast and low cost way.

The invention discloses a sleeve of a full-casing and full-slewing drilling machine. The sleeve of the full-casing and full-slewing drilling machine comprises a sleeve body, wherein the upper end of the sleeve body is connected with the slewing drilling machine; and the lower end of the sleeve body is fixedly connected with a hard alloy serrated knife. The invention further discloses a method for removing barriers in front of a cutter head of a shield tunneling machine. The method comprises the following steps: injecting bentonite in an earth pressure cabin; forming a geological drilling hole, and determining a barrier removing construction affecting range and a burial depth of the barriers in front of the cutter head of the shield tunneling machine by using a drill pipe sticking method; observing change of underground water level; determining the position of the sleeve of the full-casing and full-slewing drilling machine and tunneling to the underground part; cleaning soil bodies and the barriers in the sleeve; forming a sleeve opening in the sleeve by cutting; cleaning the barriers between the sleeve and the cutter head of the shield tunneling machine; and backfilling sandy soil in the sleeve, and gradually pulling up the sleeve in a backfilling process. The sleeve of the full-casing and full-slewing drilling machine has the beneficial effects that the positions and the burial depths of the barriers are determined rapidly, rapid drilling can be realized by the full-casing and full-slewing drilling machine, underground pressure-bearing water level on the periphery is reduced by a dewatering well, piping quicksand risks are avoided, and the opening can be formed in the sleeve to remove the barriers.

The invention discloses a method for prompting rapid recovery of vegetation in a bare sandy land and a blowout pit by combining a thoroughly decomposed sheep manure biological crust with biological measures. The technology is mainly composed of techniques such as selection of suitable grass seeds and shrubs, shrub cultivation, direct seeding of grass seeds and pavement of thoroughly decomposed sheep manure. The method comprises the steps of: firstly, selecting types of grass seeds and shrubs suitable to be grown in highly cold desert regions, and then cultivating suitable shrubs in the bare sandy land and the blowout pit; secondly, sowing the suitable grass seeds; finally paving the thoroughly decomposed sheep manure on the surface of the quicksand. After a period of time, the thoroughly decomposed sheep manure biological crust is formed on the surface of the quicksand; the suitable plant seeds and the sheep manure form a tightly combined and mutually depended integral body; the thoroughly decomposed sheep manure provides nutrition to the growth of the suitable plant seeds, has heat preservation, moisture keeping and the like functions, can promote rapid growth of the vegetation, provides a steady growth environment, avoids flow of the quicksand and wind corrosion, and is more conductive to the recovery of the desert grassland. The method for preventing and fixing sands by using sheep manure has the advantages of fast sand fixation speed, low cost, low labor cost, long storage time, rapid and convenient construction, easy operation, no adverse effect for the environment and plants, and the like.

The invention provides quicksand-type stuffing with a long shelf life and resistant to bake and premixed flour and a manufacturing method thereof. The premixed flour of the quicksand-type stuffing comprises, by mass percent, 45.78-65.45% of egg yolk powder, 15-20% of hydroxy propyl distarch phosphate, 1-3% of gellan gum, 5-10% of glucose, 10-15% of soybean dietary fibers, 1.4-5% of salt, 1-2% of sucrose fatty acid ester, 0.02-0.05% of tertiary butylhydroquinone and 0.1-0.2% of beta-carotene. The ingredients are mixed to obtain the premixed flour of the quicksand-type stuffing. The premixed flour is combined with malt syrup, anhydrous ghee, edible glycerol and citric acid so that the quicksand-type stuffing can be manufactured. The quicksand-type stuffing has taste and egg yolk flavor approximate to traditional golden quicksand-type stuffing, and is resistant to bake and long in shelf life.

The invention discloses a desert planting method. The method of the invention is applied to planting the short plants with thin main stalks. In the method of the invention, water hammer is carried out on sandlot, and holes are prepared for planting thin and small plants, thus avoiding the heavy labor for manually digging tree wells by shovels. As the tree wells are relatively small, the water poured in can guarantee the water demanding by new seedlings, water is saved and labor for additionally taking water is reduced. The seedlings are planted with water, i.e. 'water is accompanied by seedlings', and the drift sand at the openings of the holes washed out by water is used for filling the holes, thus saving procedure, filling sturdily and improving the survival rate of seedlings. A plurality of branch water pipes are arranged for simultaneous work, and the efficiency is improved. The method of the invention solves the water source problem well by utilizing the characteristic of desert that the wells with small openings can be dug easily, and the wells with small openings become the water sources for irrigation after planting. The method has the advantages of less input, saving manpower, high efficiency, survival rate of seedlings and easy to realize, and according to the local condition, the planting method can make full use of desert environment to carry out flow operation.

The invention aims to provide a series-connected type sand trapping net cage and a sand storage dam constructed by the same, belonging to the technical field of engineering. Each series-connected type sand trapping net cage with an A-shaped section consists of a front bracket, a rear bracket and sand trapping nets stretched on the front bracket and the rear bracket, the series-connected type sand trapping net cage is formed by connecting all series-connected type sand trapping net cages in series one by one along a desert, the quicksand of the desert is intercepted and trapped by the series-connected type sand trapping net cage and gradually rises, and when the height of the sandpile is 20-30 cm far from the top end of the series-connected type sand trapping net cage, the series-connected type sand trapping net cage is pulled up, the first construction structure is repeated at the top of the sandpile; when the quicksand is piled to the height 20-30 cm far from the top end of the series-connected type sand trapping net cage again, the series-connected type sand trapping net cage is lifted up according to the mode and the structure again; a check dam which takes the series-connected type sand trapping net cage as the top is formed by repeating the mode and structure for three times, four times and several times so as to achieve the purpose that the quicksand of the desert is intercepted so as not to invade inlands.

The invention discloses a desert farmland reclaiming machine and a farmland reclaiming method utilizing the same. The desert farmland reclaiming machine comprises a bulldozer, actuating arms of the bulldozer are connected with stop plates on two sides of a stirring bin, a grouting tube enters the stirring bin by penetrating one of the stop plates, a grinding roller is mounted on the bulldozer, an opening is arranged in front of the stirring bin, a shovel is arranged at the opening of the stirring bin, and a stirring device is arranged on the stirring bin. By the aid of the structure with the opening at the lower end of a front cover of the bulldozer and the shovel below the opening, quicksand or quicksand and soil on the surface layer of a desert can be quickly and conveniently shoveled into the stirring bin; since the grouting tube capable of spraying mud and the stirring device are arranged on the stirring bin, mixture of the quicksand and the mud and mixture of the quicksand and the soil in the stirring bin can be fully stirred; and due to the arrangement of the grinding roller, the repaved ground can be grinded and flattened. By the aid of the desert farmland reclaiming machine, plough layer reclamation and reformation can be well completed so as to achieve the purpose for reclaiming fertile farmlands applicable to growth of crops.

The invention relates to foundation construction field, in particular to a sand soil drainage method for foundation pit side slope. The foundation pit side slope sandy soil drainage method includes that: step 1, filter pipe fabrication; step 2, water filter pipe embedment; the foundation pit is excavated to the scale height of the sand layer, and the filter pipe fabricated in step 1 is embedded in the sandy interlayer of the side slope and is communicated with a vacuum pump; step 3, the vacuum pump is started: the pump operates to drain water; step 4, the lower soil is continuously excavated. The invention can utilize vacuum negative pressure principle to enable the vacuum dewatering filter head to be transversely laid in the quicksand layer for quickly absorbing the effluent water of the sandy interlayer, is convenient, simple and quick in treating quicksand, and has high construction efficiency.

The invention relates to sand accumulating and forest planting technology in an extremely drought Gobi sand area, which fully utilizes conditions that the Gobi sand area is open, the wind carries quicksand on the near surface and the Gobi sand area has certain flood recession to accumulate sand in planting pits, utilizes the condition that the Gobi area is close to certain flood-recession facilities to irrigate the planting pits and accumulate silts, and utilizes the condition that autumn flood is relative rich to plant forest. The technology firstly plants adaptable species in the Gobi sand area, such as narrow-leaved oleaster and Chinese tamarisk to form an early arbor-bush mixed forest, then plants bush plant species which grow quickly, such as Calligonum rubicundunm after a certain condition of accumulated sand and silt is formed in the forest belt to further strengthen sand fixing function of the forest belt, and plants less adaptable arbor tree species, such as poplar tree after relative good soil and water conditions are formed in the forest belt so as to gradually increase species diversity and strengthen comprehensive prevention function of the forest belt.

The invention relates to a quicksand high-rise residence foundation sump construction method. The construction method includes the steps: digging a sump foundation ditch to a sump bottom level, digging a small water collection well in the middle of a sump, lowering a mud pump, and covering a sand-proof steel wire net for water drawing and discharging; vertically and downwards nailing scaffold steel pipes around the sump at intervals, and erecting a double-layer formwork on the outer sides of the scaffold steel pipes in a seam-staggered manner; erecting a suspending formwork on the inner sides of the scaffold steel pipes, pouring fine aggregate concrete between the suspending formwork and the double-layer formwork to build a retaining wall around the sump, removing the mud pump in the small water collection well, and pouring fine aggregate concrete concrete to build a sump bottom thick cushion layer; bricklaying a brick moulding bed on the inner side of the retaining wall, and plastering and leveling; waterproofing, and arranging a waterproof protection layer; binding rebars and erecting a formwork for the sump, closing a valve of the water collection well, and performing reinforced concrete raft pouring on the water collection well and a foundation together. By the quicksand high-rise residence foundation sump construction method, under the premise of being without water lowering and change filling, construction of the sump can be directly performed.

The invention discloses an excavating and supporting method of a roadway containing a quicksand layer; the method comprises the following steps that (1) before the roadway is excavated, a slip casting pipe is arranged into the quicksand layer in front of an excavation direction along the design section line of the roadway, cementing slurry is injected into the quicksand layer by a slip casting pump, so that the quicksand layer is cemented together, and then an advanced temporary supporting method is adopted; (2) the roadway is excavated through a conventional excavating method, and anchor mesh spray primary supporting is carried out through a conventional supporting method after safe footage is reached; (3) anchor rope secondary supporting is carried out, a steel strand with the diameter being phi 12mm to 16mm and the length being 5m to 8m is adopted as an anchor rope, and the anchoring length needs to be more than 1m; and (4) U-shaped steel telescopic supports are used for enhancing the supporting, and the spacing between the U-shaped steel telescopic supports is 0.8m to 1.0m. According to the excavating and supporting method of the roadway containing quicksand layer, the problems that the quicksand layer is easy to collapse so that the formation of the roadway is difficult and the construction is unsafe are solved; and in addition, the supporting capability is improved, so that the deformation of the roadway after being supported is greatly improved, and the requirement of long-term stability is met.

The invention aims to provide a serial sand catching net which is fast in construction, low in cost and can achieve mechanized production, and a sand-blocking dam built by the same, which belongs to the technical field of engineering. The serial sanding catching net in the invention is formed by a nylon yarn knitted sand catching net and a steadying bar, wherein the lower part of the steadying bar is inserted a dune to be used as a spud pile; on the wandering dune, the serial sand catching net is stretched and tensed; the lower part of the steadying bar is fixed on the dune; the serial sand catching net is erected one by one according to the designed line to be constructed into a sand catching net for the sand blocking dam; thus, flowing sand in deserts can be intercepted and captured by the sand catching net and is accumulated in inner and external sides of the sand catching net for the sand blocking dam to form the sand blocking dam.

The invention provides a method for growing shiny-leaved yellowhorn in quick-sand and desertification regions. The method comprises the following steps of: soaking the root of shiny-leaved yellowhorn nursery stock into a 2-6% rooting powder aqueous solution, planting the nursery stock into a pit the area of which is not less than 50*50cm<2>, placing a water-retaining agent absorbing enough water into the pit, then covering with soil for 1-2cm, fertilizing, slightly lifting the nursery stock, then covering with soil again, treading to be firm and watering; or carrying out bud forcing treatment on shiny-leaved yellowhorn seeds, planting umbilici into a pit of which the area is not less than 50*50cm<2> broadways, and placing a water-retaining agent absorbing enough water into the pit, covering fat soil for 1-1.5cm, fertilizing, covering soil again, treading to be firm and watering. The plating experiment in quick-sand and desertification regions in Ninxia shows that the rate of emergence of the shiny-leaved yellowhorn can be 99%, the rate of survival can be 95%, and the shiny-leaved yellowhorn grows well. The method provided by the invention can be used for realizing the aims of fixing quick sands, beautifying the environment and improving the quick sands and soil, and at the same time, the method also can be used for bringing good economic benefits for people in desert zone, and improving the living environment and financial situation of people in desert zone.

The invention is a quicksand slope depth-type sand fixing method, comprising the steps of: adopting the flower pipe-micro root pile depth-type sand fixing method to carry out quicksand slope depth-type sand fixing design, i.e. drilling vertically the ground to the sand slope depth on a sand slope necessary to fix sand, inserting micro flow pipe into the hole and injecting high pressure clay, soil powder / cement and fine sand pulp into the flower pipe, so that the pulp is ejected through pores around the flower pipe to form rootlike pulp veins, which tightly hold the sand by their bonding and absorbing actions, so as to achieve the sand fixing purpose. And it can effectively fix the quicksand slope.

The invention discloses a construction method for processing an ultra-thick quicksand layer of a pile foundation by using a front-end vibration steel casing. The construction method comprises the following steps of: pre-manufacturing a front-end vibration sinking steel casing, and welding a steel clapboard in the steel casing along the axial direction of the steel casing, wherein the plane of the steel clapboard is parallel to the axial line of the steel casing; after manually digging holes to the quicksand layer, installing and sinking the steel casing in the pile hole in a vibrating manner; and, after sinking the steel casing in a mudstone layer below the quicksand layer in a vibrating manner, stopping tunnelling while manually digging at the position which is 30 cm away from the bottom of the steel casing, implanting a ring of steel bars, each of which is 100 cm in length, in the remained quicksand layer and the mudstone layer at the lower part of the quicksand layer along the edge of the casing, then, continuously and downwardly tunnelling the mudstone layer below the quicksand layer in 30 cm, and pouring a waterproof reinforced concrete protective wall which is 60 cm in height and 4 cm in thickness. The construction method disclosed by the invention is capable of rapidly and efficiently passing through the quicksand layer in the event of not influencing ground construction fields and not damaging stratum structures; furthermore, the construction method has the advantages of low cost and high safety.

The invention provides a construction method for digging a deep foundation pit in a large-thickness highly weathered sandstone stratum in a combined supporting mode, and relates to the technical field of complex geology deep foundation pit supporting construction in constructional engineering. According to the construction method, highly weathered sandstone stratum supporting is divided into two parts, the upper part of the sandstone stratum adopts a hollow anchor bolt shotcrete and rock bolt supporting mode, and a high-pressure jet grouting pile supporting mode is adopted 3 meters above a base. By means of the construction method, the problems in excavation, water sealing-up and supporting under the complex geology conditions that the highly weathered sandstone is not exposed evenly and large in thickness, and fissure water is not distributed evenly are solved effectively, the phenomena of fissure water and subsurface erosion of the large-thickness highly weathered sandstone stratum are effectively prevented, and softening and quicksand of the base are prevented.