CN105908765B - For protecting the open trench tunnel water sealing structure and construction method of groundwater environment - Google Patents

For protecting the open trench tunnel water sealing structure and construction method of groundwater environment Download PDF

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Publication number
CN105908765B
CN105908765B CN201610425630.2A CN201610425630A CN105908765B CN 105908765 B CN105908765 B CN 105908765B CN 201610425630 A CN201610425630 A CN 201610425630A CN 105908765 B CN105908765 B CN 105908765B
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China
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frozen soil
sealing layer
freezing
horizontal
soil sealing
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CN201610425630.2A
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Chinese (zh)
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CN105908765A (en
Inventor
刘建友
吕刚
陈学峰
马福东
谭富圣
王杨
彭斌
于鹤然
宋月光
朱敏
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中铁工程设计咨询集团有限公司
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    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D19/00Keeping dry foundation sites or other areas in the ground
    • E02D19/06Restraining of underground water
    • E02D19/12Restraining of underground water by damming or interrupting the passage of underground water
    • E02D19/14Restraining of underground water by damming or interrupting the passage of underground water by freezing the soil
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D31/00Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D31/00Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution
    • E02D31/002Ground foundation measures for protecting the soil or subsoil water, e.g. preventing or counteracting oil pollution
    • E02D31/004Sealing liners

Abstract

The present invention relates to underground engineering technologies, in particular to for protecting the open trench tunnel water sealing structure and its construction method of groundwater environment.The open trench tunnel water sealing structure includes:It is set to the vertical frozen soil sealing layer of tunnel open excavation foundation pit two sides, and it is set to the horizontal direction frozen soil sealing layer of the tunnel open excavation bottom of foundation ditch, the vertical frozen soil sealing layer and horizontal direction frozen soil sealing layer intersection, the bottom of the vertical frozen soil sealing layer are lower than the bottom of the horizontal direction frozen soil sealing layer.The present invention is protected groundwater environment, is avoided polluted underground water water quality during constructing tunnel using vertical frozen soil sealing layer, the frozen soil sealing layer of horizontal direction frozen soil sealing layer building U-lag.By using water sealing structure is freezed, avoid a wide range of drainage construction, saved valuable groundwater resources, at the same avoid periphery caused by drainage construction it is neighbouring build, the sedimentation and deformation of structures.

Description

For protecting the open trench tunnel water sealing structure and construction method of groundwater environment

Technical field

The present invention relates to underground engineering technologies, in particular to for protecting the open trench tunnel sealing of groundwater environment Structure and construction method.

Background technique

Subway construction for region of FuShui, when subway tunnel uses cut and cover tunneling, using sealing or drainage position Underground water within the scope of reason tunnel excavation is the element task before tunnel excavation.Currently, China's subway tunnel sealing generally uses Ejection for water plugging or rotary churning pile water stopping, both sealing modes require to inject cement grout into soil layer, polluted underground water water Matter, while cement grout flow direction is not easy to control, is easy the seepage channel of blocking underground water, changes the percolation path of underground water.And Using drainaging scheme, by the valuable groundwater resources of waste, while draining caused level of ground water reduction and easily causing periphery neighbouring It builds, the sedimentation and deformation of structures.

With urbanization progress and economic development, subway solves one of the main means of urban transport problems by becoming.But It is that it is all kinds of often to cause surface subsidence, karst collapse, wall rock destabilization etc. during subway construction since geological conditions difference is larger The problems of geo-environment can also cause all kinds of water environmental problems such as tunnel gushing water, water level decreasing, water pollution.

To avoid all kinds of engineering problems caused in Metro Construction or reducing influence of the subway engineering to surrounding enviroment, Domestic and foreign scholars have carried out a large amount of research to correlative protection governing measure and method.Albert Weiler (1983) is based on moral Will Duisburg Quaternary Strata condition sums up subway construction method-gap concretion method.Sun Yazhe (2003) is directed to Nanjing Traffic tunnel is built there may be the problems of geo-environment such as water pollution, surface subsidence, surface collapse, tunnel gushing waters under the XuanWu Lake, To reduce the influence to groundwater environment, it is proposed that limitation cutting depth and protection natural sludge layer, using banketing for good water permeability The small construction material of material, pollution, chemical grout avoid large area artificial rainmaking using freezing sealing construction scheme.It sets a prairie fire side (2004) it is directed to influence of the karst to Guangzhou Metro Construction, proposes to carry out karst water segregation using freezing and High-Pressure Grouting Method, To solution cavity using grouting and pattern handling.Xing Wei river bend (2004) analyze Metro Construction may be to the influence of water quality, it is proposed that Using small construction material and chemical grout is polluted in engineering construction, the change for analyzing groundwater flow condition can also make Engineering stability be deteriorated cause differential settlement, it is proposed that optimization each construction parameter of shield, and using corresponding engineering method such as every Disconnected, soil stabilization, structure trunk reinforcing and foundation underpinning etc. are to reduce the influence to ambient enviroment.C.O.Aksoy(2008) The surface subsidence problem for analyzing the initiation of Turkey's Izmir subway station engineering dewatering maintains country rock by chemical grouting means Stability effectively prevents surface subsidence and restores level of ground water to previous level.Li Guangtao (2009) is for Guangzhou Molten, soil cave unfavorable geological condition present in No. three line engineering constructions of iron is handled, and the rock of shield and open cut is clearly proposed Molten treatment measures.R.Galler (2009) proposes the new Austrian method for tunnel construction (NATM) of a set of economic security, the party Method was rapidly developed in recent years in Australia.Fu Zhifeng (2010) is for possible in No. 2 line engineering constructions of Wuhan subway The geotechnical engineering problems such as quaternary formation, Karst Geological Landscape, the underground water of appearance, propose engineering dewatering design, diaphram wall, Slip casting blocks the precautionary measures such as waterproofing work.Long Yankui (2012) analyzes influence of the karst to subway engineering, emphatically to karst The influence factor of cave stability is explored, and proposes the karst cave of digging up and filling in, slip casing by pressure, works leap Treatment measures.It is therefore seen that the previous treatment research focused on to certain the problems of geo-environment, and it is anti-for engineering should be carried out. more Shield processing takes into account spring water again and the research of water quality protection is also more rare at present.

Summary of the invention

The purpose of the present invention is to provide a kind of for protecting the open trench tunnel water sealing structure and construction party of groundwater environment Method, the problem of to solve in tunnel work progress to Groundwater Pollution, protect groundwater resources.

The embodiment of the present invention provides a kind of for protecting the open trench tunnel water sealing structure of groundwater environment comprising:Setting Vertical frozen soil sealing layer in tunnel open excavation foundation pit two sides, and be set to the horizontal direction frozen soil of the tunnel open excavation bottom of foundation ditch and stop Water layer, the vertical frozen soil sealing layer and horizontal direction frozen soil sealing layer intersection, the bottom of the vertical frozen soil sealing layer are low In the bottom of the horizontal direction frozen soil sealing layer.

In some embodiments, preferably, tunnel open excavation foundation pit two sides ground is laid with insulating layer;The insulating layer packet It includes:Eps foam plate, polystyrene, extruded sheet or polyurethane sheet.

In some embodiments, preferably, the medial surface and the horizontal direction frozen soil sealing of the vertical frozen soil sealing layer The medial surface of layer is injected with thermal insulation concrete.

In some embodiments, preferably, the thermal insulation concrete includes:Air entrained concrete, 0.5%~2% it is efficient Accelerator, 0.5%~2% latex powder and 3%~7% fiber.

In some embodiments, preferably, the vertical frozen soil sealing layer with a thickness of 1~3 meter;And/or the level To frozen soil sealing layer with a thickness of 1~3 meter.

In some embodiments, preferably, the distance between two neighboring described tunnel open excavation foundation pit is 20~80 meters.

In some embodiments, preferably, the horizontal direction frozen soil sealing layer and the vertical frozen soil sealing layer are averaged Temperature is not higher than -10 DEG C.

In some embodiments, preferably, the vertical frozen soil sealing layer includes vertical freezing hole, the vertical freezing hole Diameter be 50~200 millimeters;Spacing between the vertical freezing hole is 500~1000 millimeters.

In some embodiments, preferably, the horizontal direction frozen soil sealing layer includes horizontal direction freezing hole, the horizontal direction The diameter of freezing hole is 50~200 millimeters.

In some embodiments, preferably, the spacing between the horizontal direction freezing hole is 500~1000 millimeters.

In some embodiments, preferably, the clear spacing of the horizontal direction freezing hole and tunnel floor panel structure outer profile is 200~800 millimeters.

The construction method for the open trench tunnel water sealing structure that the present invention also provides a kind of for protecting groundwater environment, packet It includes:

Constructing tunnel is divided into multiple construction sections;

In the excavation starting point of each construction section, construction shaft is set;

It is drilled down into vertical freezing hole from ground in the two sides of default tunnel open excavation foundation pit position, is crept into below tunnel floor Freezing hole, the tripping in freezing pipe in freezing hole, the tripping in liquid supply pipe in the freezing pipe;

Refrigeration system is freezed in installation, will freeze refrigeration system and is connected respectively with thermometer hole, liquid supply pipe;

Freeze operation is carried out, vertical frozen soil sealing layer, horizontal direction frozen soil sealing layer are constructed;

After vertical frozen soil sealing layer, the thickness of horizontal direction frozen soil sealing layer and intensity reach preset requirement, freeze to apply After work enters maintenance freezing period, layer-by-layer excavation pit;

Thermal insulation concrete is sprayed, tunnel lining structure is constructed.

In some embodiments, preferably, the drilling of the freezing hole includes:

Determine freezing pipe, relief tube, the specification of liquid supply pipe, equipment of drilling;

Drilling machine platform is built, position is increased in the drilling machine platform setting layering;

Freezing hole aperture, the drilling mounting hole pipe of each freezing hole;

By the fixed drilling machine of freezing hole design orientation, freezing pipe is put into drilling, to seal head after projected depth under freezing pipe Portion seals the gap of freezing pipe and orifice tube;Freezing pipe and freezing hole concentricity, freezing hole leak test pressure is in 0.7~1.0MPa;

The tripping in liquid supply pipe in freezing pipe, liquid supply pipe bottom end welding support, and outlet and circuit goat's horn are installed, and freeze Pipe end-cap.

In some embodiments, preferably, described to freeze in refrigeration system, in outlet saline line, circuit saline line It is respectively mounted pressure gauge, temperature sensor, control valve;And/or Brine Pipe outlet installation flowmeter;And/or brine distributing ring and freeze Tie two valves that control freezing phase brine flow is installed between device;And/or the eminence of saline line installs vent valve;With/ Or, refrigerant agent uses calcium chloride solution, specific gravity 1.265.

In some embodiments, preferably, polystyrene foam plastics insulating layer, modeling are set gradually outside the saline line Expect film.

In some embodiments, preferably, the refrigeration system of freezing further includes:Unit is freezed, the freezing unit Evaporator and cryogenic pipe are kept the temperature with flex foam, and brine tank and salt water conduit tube are kept the temperature with polystyrol plastic foam plate.

In some embodiments, preferably, the freeze operation includes:

In the case where adjusting pressure, temperature at any time, refrigeration system is freezed in operating;

In freezing process, timing detects brine temp, brine flow and frozen soil sealing layer spread scenarios;

It determines that horizontal direction frozen soil sealing layer has formed loop connecting structure, and reaches preset thickness;

Determine inside horizontal direction frozen soil sealing layer in non-frozen soil 2 meters it is upper without jelly water;

After being excavated in soil layer, determine that thickness, surface temperature and the deformation of horizontal direction frozen soil sealing layer reach preset requirement;

Enter maintenance freezing period after excavation of foundation pit;In maintenance freezing period, if frozen soil sealing layer expansion rate is more than preset value, Bearing capacity, the super pre-value of stability of frozen soil sealing layer improve brine temp then in the case where brine temp is not higher than -20 DEG C.

The open trench tunnel water sealing structure and its construction method provided in an embodiment of the present invention for being used to protect groundwater environment, with The prior art is compared, and using vertical frozen soil sealing layer, the frozen soil sealing layer of horizontal direction frozen soil sealing layer building U-shaped, prevents open cut Underground water outside foundation pit enters U-lag, while protecting groundwater environment, avoids polluted underground water water during constructing tunnel Matter.By using water sealing structure is freezed, a wide range of drainage construction is avoided, valuable groundwater resources has been saved, has avoided simultaneously Periphery caused by drainage construction is neighbouring to be built, the sedimentation and deformations of structures.

By the way that thermal insulation concrete is arranged between tunnel-liner and frozen soil sealing layer, the heat insulating ability of frozen soil sealing layer is improved Can, the heat transfer in frozen soil sealing layer and tunnel is slowed down, considerably reduces and freezes expense.

Detailed description of the invention

Fig. 1 is in one embodiment of the invention for protecting the cross-sectional signal of the open trench tunnel water sealing structure of groundwater environment Figure;

Fig. 2 is the schematic diagram for freezing refrigeration system in one embodiment of the invention in open trench tunnel water sealing structure.

Note:1 horizontal direction frozen soil sealing layer;2 vertical frozen soil sealing layers;3 vertical freezing pipes;4 horizontal direction freezing pipes;5 heat preservations Concrete;6 ground insulating layers;7 tunnel structures;8 fresh water pumps;9 freezing units;10 starting cabinets;11 brine tanks;12 brine pumps;13 Freezing pipe;14 cooling towers.

Specific embodiment

The present invention is described in further detail below by specific embodiment combination attached drawing.

In view of water is Source of life and the precious resources that city is depended on for existence and development, China has more than half City there are problems that lacking, and therefore, it is engineering technology that valuable groundwater resources how are protected during metro construction The key technical problem that personnel intend to solve, such as this city well-known with spring in Jinan, protect the water quality and water of spring, Matter of utmost importance even more in subway construction.The technical issues of present invention intends to solve be in region of FuShui subway tunnel process of construction such as What protection underground water realizes safely and fast efficiently excavating for subway tunnel in the case where not precipitation.Therefore solution is clearly required The technical issues of be:

(1) pollution problem of the constructing metro tunnel in the process to quality of groundwater is solved;

(2) protection of the constructing metro tunnel in the process to underground water water resource is solved, avoids reducing groundwater level, avoid Change seepage action of ground water path, protects spring.

The open trench tunnel water sealing structure for protecting groundwater environment is provided thus comprising:It is set to tunnel open excavation The vertical frozen soil sealing layer of foundation pit two sides, and it is set to the horizontal direction frozen soil sealing layer of the tunnel open excavation bottom of foundation ditch, it is described Vertical frozen soil sealing layer and horizontal direction frozen soil sealing layer intersection, the bottom of the vertical frozen soil sealing layer are lower than the level To the bottom of frozen soil sealing layer.

Using vertical frozen soil sealing layer, the frozen soil sealing layer of horizontal direction frozen soil sealing layer building U-shaped, prevent outside open-cut foundation ditch The underground water in portion enters U-lag, while protecting groundwater environment, avoids polluted underground water water quality during constructing tunnel.Pass through Using water sealing structure is freezed, a wide range of drainage construction is avoided, has saved valuable groundwater resources, while avoiding draining and applying Periphery caused by work is neighbouring to be built, the sedimentation and deformation of structures.

Next, the technology is described in detail:

It is a kind of for protecting the open trench tunnel water sealing structure of groundwater environment, as shown in Figure 1, including:It is bright to be set to tunnel The vertical frozen soil sealing layer 2 of foundation pit (inside setting tunnel structure 7) two sides is dug, and is set to the level of the tunnel open excavation bottom of foundation ditch To frozen soil sealing layer 1, the vertical frozen soil sealing layer 2 and the horizontal direction frozen soil sealing layer 1 intersection constitute U-shaped groove structure, institute The bottom for stating vertical frozen soil sealing layer 2 is lower than the bottom of the horizontal direction frozen soil sealing layer 1.It is applied in the setting of tunnel excavation starting point Work vertical shaft moves towards tunnel being divided into several freeze along tunnel line generally using Metro station excavation as construction shaft Section, each freezing segment length is about 20~80 meters.Stop the inner excavation foundation pit of water layer structures in U-lag frozen soil, places open cut base Underground water outside hole enters U-lag.The mean temperature of effective frozen soil sealing layer is not higher than -10 DEG C, frozen soil sealing layer when excavation Surface temperature is lower than -3 DEG C.

The thickness of vertical frozen soil sealing layer 2 is according to parameters such as excavation of foundation pit depth, foundation pit two sides Water And Earth Pressures, ground loads It determines, the requirement of soil at both sides stability need to be met, thickness is intended to be 1.0m~3.0m range, the depth of vertical frozen soil sealing layer 2 Degree should be greater than the depth of horizontal frozen soil sealing layer at tunnel floor.

Horizontal direction frozen soil sealing layer 1 is set to tunnel floor hereinafter, forming closed circumferential frozen soil sealing collar, and horizontal direction is frozen The thickness of native sealing layer 1 is intended to be 1.0m~3.0m range.The length of horizontal direction frozen soil sealing layer 1 is determining according to segment length is freezed, It is intended to be 20~80m.

The construction of vertical frozen soil sealing layer 2:In foundation pit two sides corresponding position, vertical freezing is directly set downwards from ground Vertical freezing pipe 3 is arranged in vertical freezing hole, freezes bore dia in 50mm~200mm, freezes 500~1000mm of pitch of holes for hole.

The construction of horizontal direction frozen soil sealing layer 1:The construction shaft of starting point or the work in each freeze section junction in tunnel Make hole and set horizontal direction freezing hole, horizontal direction freezing pipe 4 is set in horizontal direction freezing hole, and horizontal direction freezing hole is arranged at foundation pit bottom Portion freezes the quasi- selection 50mm~200mm of bore dia, freezes 500~1000mm of pitch of holes, freezing hole and tunnel floor structure foreign steamer Wide clear spacing is intended to be 200~800mm.Freezing pipe, lower infusion tube in freezing pipe are descended in freezing hole.

In order to reduce energy consumption, the heat insulation effect of refrigeration system is improved, insulating layer is laid on foundation pit two sides ground, in U Thermal insulation concrete 5 is sprayed on the inside of shape slot water sealing structure, collectively forms heat-insulation system.Ground insulating layer 6 can be selected eps foam plate, The heat preservation plate materials such as polystyrene, extruded sheet, polyurethane sheet.Injection thermal insulation concrete 5 on the inside of U-lag water sealing structure is opened with foundation pit It digs successively injection, jet thickness and is intended to be 10~30cm.Thermal insulation concrete 5 is also known as air entrained concrete, foam concrete, foams and mix Solidifying soil, belongs to the scope of heat preserving and insulating material, can prevent or reduce heat exchange occurs with extraneous, and that reduces that heat dissipates has one Determine the special concrete of Physical and mechanical properties.

Thermal insulation concrete is constructed using wet shot method, in order to reduce the mobility of foam concrete, improves viscosity and attachment Power, in foam concrete increase by 0.5%~2% (BASF) efficiently accelerator, 0.5%~2% (ternary) latex powder and 3%~7% fiber.

The construction method of above-mentioned open trench tunnel water sealing structure is provided below, specifically includes:

Step 101, constructing tunnel is divided into multiple construction sections;

Step 102, construction shaft is set in the excavation starting point of each construction section;

Step 103, freezing pipe creeps into work;

First part:Freezing pipe, temperature tube, relief tube and liquid supply pipe specification

108 × 8mm of ф low-carbon seamless steel pipe can be selected in freezing pipe, and single pipe length is 1.5~2m, using threaded connection And manual repair welding, temperature tube and the same freezing pipe of hydrology pipe tubing.62 × 6mm of liquid supply pipe ф can be selected enhancing vinyl tube or 15#Steel pipe.

Second part:It drills lectotype selection

2, MKG-5S type drilling machine can be selected.2, BW-250/50 slush pump, flow 250l/min can be selected.Drilling machine and Slush pump general power is 41kw.

Freezing hole drilling special combination drilling tool pipe-following drilling can be used.Special TY-1 type high-precision can be used in drillhole inclination survey Horizontal drilling gyrolevel, drilling superficial part are calibrated with theodolite Inclination Measurement by Light.

Part III:Freezing hole quality requirement

According to construction reference point, freezing hole is arranged by freezing hole construction figure.Hole location deviation should not exceed 100mm.Freezing hole 110mm can be selected in aperture.Freezing hole drilling depth error is -0.2~+0.3m.Hole deviation controls within 0.8 ‰.

Part IV:Drilling machine platform is built

Drilling machine platform is built using full hall scaffold pipe, and scaffold tube interplanar spacing is 0.6m × 0.6m.Platform is completely spread 60mm thickness deal board, borer chassis underlay 200mm × 200mm lumps of wood.According to hole site is freezed, drilling machine platform is increased in layering.

Step 104:It is drilled down into vertical freezing hole from ground in the two sides of default tunnel open excavation foundation pit position, in tunnel floor Creep into freezing hole, the tripping in freezing pipe in freezing hole, the tripping in liquid supply pipe in the freezing pipe in lower section;

The step specifically includes:

Step 104-1, freezing hole aperture

Freezing hole can use the core drill aperture of Φ 160mm diamond.Each drilling mounting hole pipe, orifice tube can use ф 159 The processing of × 8mm seamless steel pipe.When drilling, orifice tube mounting hole sealing device.

Step 104-2, freezing hole drilling are installed with frigo

1. by the fixed drilling machine of freezing hole design orientation requirement.Freezing pipe is put into drilling.To after projected depth under freezing pipe Seal header joints.

2. in order to guarantee borehole accuracy, aperture section drilling is crucial.When creeping into preceding 10~20m, drilling rod side is checked repeatedly To, adjustment drilling machine position, and can continue to creep into after detecting deflection no problem with theodolite or gyroscope.

3. to be first piped before in freezing pipe tripping in hole, guarantee freezing pipe concentricity.Under after good freezing pipe, carried out with inclinometer Deviational survey, then repetition measurement freezes hole depth.Tube head is freezed in sealing after freezing length of tube and deflection qualification, and carries out suppressing leak test. Freezing hole leak test pressure controls between 0.7~1.0MPa, and stablizing 30 minutes unchanged persons of pressure is that pressure testing is qualified.

4. freezing pipe is after the installation is completed, with the gap of plugging material sealing freezing pipe and orifice tube.

5. the tripping in liquid supply pipe in freezing pipe.The effective pipe collar connection of feed flow, the bracket of 0.2m high is welded in liquid supply pipe bottom end.So Installation goes, circuit goat's horn and freezes pipe end-cap afterwards.

Thermometric hole construction method is identical as freezing pipe.

Step 105, installation freeze refrigeration system, will freeze refrigeration system respectively with freezing pipe 13, thermometer hole, liquid supply pipe phase Even;

The installation diagram for freezing refrigeration system can refer to attached drawing 2.Installation steps specifically include:

Step 105-1 freezes refrigeration equipment type selecting and circuit design

1. YSKF600 type, which can be selected, freezes 1 set of unit, YSKF300 type each 2 sets of unit of freezing (wherein 1 set spare).Work as salt Coolant-temperature gage is at -30 DEG C, and when cooling water temperature is 28 DEG C, the refrigerating capacity of Freezing Station is about 240000kcal/h, freezes 9 motor of unit General power is 305kw.

2. 8Sh-13 (A) salt water circulating pump 2 (wherein 1 spare), flow 270m3/h, lift 36m, motor can be selected Power 45kw;IS200-150-250 cooling water circulating pump 1, flow 400m3/h, lift 20m is selected, motor general power 37kw;.

3. DBN3-200 type cooling tower 14,2, motor general power 11kw can be selected.

4. brine tank 11 is set, one, volume 6m3.

5. salt water conduit tube sum aggregate liquid distribution pipe selects ф 219 × 8mm seamless steel pipe, salt water conduit tube length is 380m.Collect, match Liquid pipe is connect with goat's horn selects 1.5 " high-pressure rubber pipes.

6. " welded tube installs thermometer in refrigerator inlet and outlet pipes to cooling water pipe with 5.

7. going, installing pressure gauge, temperature sensor and control valve in the saline line of circuit.It exports and installs in Brine Pipe Flowmeter.

8. installing two, valve, between brine distributing ring and frigo so as to control freezing device brine flow.

9. the eminence in saline line installs vent valve.

10. salt water and clear water pipeline pressure resistance are respectively 0.7MPa and 0.3MPa.

(11) the cooling water amount of each Freezing Station is 30m3/h, maximum total electricity consumption about 398kw.

(12) other:Refrigerator oil selects N40 refrigerator oil.Refrigerant selects R22 refrigerant.Refrigerant agent is molten using calcium chloride Liquid is as refrigerating cycle salt water.Salt water specific gravity is 1.265.

Step 105-2, the installation of Freezing Station Housing, Furniture, Furnishing And Equipment

Station equipment mainly includes power distribution cabinet (i.e. starting cabinet 10), freezing unit 9, brine tank 11, brine pump 12, fresh water pump 8, cooling tower 14 and clear water reserviors etc..Equipment is installed to be carried out by the requirement of equipment operating manual.

Control valve is installed between water pump inlet and outlet, salt water conduit tube both ends, collection brine distributing ring and frigo.Condenser into Outlet installation temperature measuring point;Going to circuit salt water conduit tube both ends that temperature and pressure measuring point is installed;The salt water conduit tube outlet installation in circuit Electromagnetic flowmeter;Flow measurement circuit is installed between each frigo and collection brine distributing ring;In brine tank installation liquid level instruction report Alert device.

In some embodiments, Freezing Station assembled prefabricated house, 3.5 meters of clear height, wall and roof are laid with soundproof plate, clear water reserviors With brick masonry, cement plaster, pond is 0.7 meter high.

Step 105-3, piping connection, heat preservation and test instrumentation are installed

Salt water and cooling water pipeline with pipe support directly on the ground, flanged joint.It goes, circuit salt water conduit tube pipe support is consolidated It is scheduled on the active well borehole wall.Thermometer, pressure gauge and flowmeter installation are carried out by design.Saline line is used after leak test, cleaning Polystyrene foam plastics heat preservation, the outside of insulation layer thickness 50mm, insulating layer are wrapped up with plastic film.

Freeze the evaporator of unit and the flex foam heat preservation of cryogenic pipe 50mm thickness, brine tank and salt water conduit tube It is kept the temperature with the polystyrol plastic foam plate of 50mm thickness.

Step 105-4, dissolves calcium chloride and unit fills fluorine oiling

About 1/4 clear water is first injected in brine tank, then turn on pump recycles and be gradually added solid calcium chloride, until salt water Concentration reaches design requirement.Impurity is removed when dissolving calcium chloride.Salt water in brine tank cannot fill too full, in order to avoid it is higher than salt Brine tank is overflowed when the freezing pipe salt water reflux of tank port.

Unit fills fluorine and refrigerator refuels and carries out according to the requirement of equipment operating manual.The inspection of refrigeration system is carried out first Leakage and nitrogen rinse, and after ensuring system ne-leakage, then fill fluorine oiling.

Step 106, freeze operation is carried out, vertical frozen soil sealing layer, horizontal direction frozen soil sealing layer are constructed;

The step includes:

Step 106-1, freezing system test running with actively freeze

Equipment carries out debugging and test running after the installation is completed.In test running, each state such as pressure, temperature is adjusted at any time Parameter runs unit under the conditions of in relation to the technical parameter of technological procedure and design requirement.In freezing process, timing is detected Brine temp, brine flow and frozen soil sealing layer spread scenarios,

Freezing system operating parameter is adjusted when necessary.Freezing system enters after working well actively to be freezed.It is required that in one week Brine temp is down to -20 DEG C or less.

Step 106-2, examination is dug to be freezed with maintenance

It is observed according to hydrology hole and determines that frozen soil sealing layer has handed over circle, and judge that frozen soil sealing layer reaches according to observed temperature After design thickness, then with core drill 2m or more in non-frozen soil is squeezed into inside frozen soil sealing layer, without moving water in confirmation frozen soil sealing layer. It is then possible to which subregion opens the active well borehole wall.After being excavated in soil layer, thickness, surface temperature and the change of frozen soil sealing layer are surveyed Shape such as has reached design requirement, then can enter normal construction, otherwise should stop tunneling, reinforce freezing, and analyze reason, take Corresponding measure.

Enter maintenance freezing period after excavation of foundation pit.In principle, brine temp and brine flow are freezed in the maintenance during excavation With actively freeze identical, as according to site-test analysis, proved really in construction, frozen soil sealing layer expansion rate is faster than estimated, freezes Native sealing layer has enough bearing capacities and stability, has met design requirement, can properly increase brine temp, but highest cannot Higher than -20 DEG C.Start after doing liner, in the case where ensuring outer lining safety, brine temp can be improved, or even stops freezing in advance Knot.

Step 107, when vertical frozen soil sealing layer, the thickness of horizontal direction frozen soil sealing layer and intensity reach preset requirement Afterwards, after frozen construction enters maintenance freezing period, layer-by-layer excavation pit;

When frozen soil layer effective thickness and intensity reach requirement, frozen construction enters layer-by-layer excavation pit after maintenance freezing period, When excavation, the soil layer for selecting hand excavation not freeze first recycles pneumatic pick to tunnel frozen soil.Pay attention to:Freezing curtain exposure temperature Must not spend and be higher than -5 DEG C, and exposure duration control is in for 24 hours.

Step 108, tunnel lining structure is constructed.

The step specifically includes:

Step 108-1 sprays thermal insulation concrete

One layer of heat preservation concrete is sprayed after excavation of foundation pit in time, jet thickness is intended to be 10~30cm.Thermal insulation concrete uses The construction of wet shot method improves viscosity and adhesive force, increases in foam concrete to reduce the mobility of foam concrete The efficient accelerator of 0.5%~2% BASF, 0.5%~2% ternary latex powder and 3%~7% fiber.

When excavation of foundation pit is to projected depth, one layer of heat preservation concrete is sprayed in bottom of foundation ditch, thickness is intended to be 10~30cm.

Step 108-2, pours Tunnel Second Lining

Tunnel-liner should ensure that lining thickness and lapped length of steel bar.Strict control measurement prevents tunnel to owe to dig, and reinforcing bar is tied up When bundle, special messenger is responsible for, and circumferential, the longitudinal reinforcement lap of splice is respectively 35~25 times of bar diameter.

To guarantee that strength of lining is not less than the requirement of C30, concrete mix proportion experiment should be made before construction, determined by test Optimum mix, and be strictly controlled, make up to design requirement.

Lining cutting is using homemade simple steel formwork trolley construction, and strict control die shape size cannot invade lining when formwork erection Inner outline is built, and is no more than 50mm outward, is responsible for by footman survey crew, and blocked up bulkhead, to guarantee outside form joint Not spillage liquid.

To accelerate concrete hardening and preventing part freezing, the J851 that cement weight 2.5%~4% is added in concrete is early The MRT early strength antifreezing agent of strong antifreeze water-reducing agent and cement weight 3%~4%, both materials have improvement concrete and easy Property and density, enhance the anti-permeability performance and freexing tolerance of concrete, and reinforce concrete vibrating in construction, prevent honeycomb fiber crops Face.

Tunnel-liner should reinforce the continuity of concrete construction, reinforce to concrete curing, to prevent frozen soil to concrete There is freeze injury.

The present invention has the following advantages that:

(1) groundwater environment is protected, polluted underground water water quality during constructing tunnel is avoided.

(2) by using water sealing structure is freezed, a wide range of drainage construction is avoided, has saved valuable groundwater resources, Avoid simultaneously periphery caused by drainage construction it is neighbouring build, the sedimentation and deformation of structures.

(3) by the way that thermal insulation concrete is arranged between tunnel-liner and frozen soil sealing layer, the guarantor of frozen soil sealing layer is improved Warm nature energy, slow down frozen soil sealing layer with the heat transfer in tunnel, considerably reduce and freeze expense.

The foregoing is only a preferred embodiment of the present invention, is not intended to restrict the invention, for the skill of this field For art personnel, the invention may be variously modified and varied.All within the spirits and principles of the present invention, made any to repair Change, equivalent replacement, improvement etc., should all be included in the protection scope of the present invention.

Claims (10)

1. a kind of for protecting the open trench tunnel water sealing structure of groundwater environment, which is characterized in that including:It is set to tunnel open excavation The vertical frozen soil sealing layer of foundation pit two sides, and it is set to the horizontal direction frozen soil sealing layer of the tunnel open excavation bottom of foundation ditch, it is described Vertical frozen soil sealing layer and horizontal direction frozen soil sealing layer intersection, the vertical frozen soil sealing layer and horizontal direction frozen soil sealing layer The frozen soil sealing layer of U-shaped is constructed, the bottom of the vertical frozen soil sealing layer is lower than the bottom of the horizontal direction frozen soil sealing layer, with Prevent the underground water outside open-cut foundation ditch from entering U-lag;
The construction of horizontal direction frozen soil sealing layer:In tunnel, the construction shaft of starting point or the working pit in each freeze section junction are beaten If horizontal direction freezing hole, horizontal direction freezing pipe is set, horizontal direction freezing hole is arranged in bottom of foundation ditch in horizontal direction freezing hole.
2. as described in claim 1 for protecting the open trench tunnel water sealing structure of groundwater environment, which is characterized in that the tunnel Road open-cut foundation ditch two sides ground is laid with insulating layer;The insulating layer includes:Eps foam plate, polystyrene, extruded sheet or poly- ammonia Ester plate.
3. as described in claim 1 for protecting the open trench tunnel water sealing structure of groundwater environment, which is characterized in that described perpendicular The medial surface of medial surface and the horizontal direction frozen soil sealing layer to frozen soil sealing layer is injected with thermal insulation concrete.
4. as claimed in claim 3 for protecting the open trench tunnel water sealing structure of groundwater environment, which is characterized in that the guarantor Warm concrete includes:Air entrained concrete, 0.5%~2% efficient accelerator, 0.5%~2% latex powder and 3%~7% Fiber.
5. as described in claim 1 for protecting the open trench tunnel water sealing structure of groundwater environment, which is characterized in that described perpendicular To frozen soil sealing layer with a thickness of 1~3 meter;And/or the horizontal direction frozen soil sealing layer with a thickness of 1~3 meter;And/or phase The distance between adjacent two described tunnel open excavation foundation pits are 20~80 meters;And/or the horizontal direction frozen soil sealing layer and described perpendicular - 10 DEG C are not higher than to the mean temperature of frozen soil sealing layer.
6. according to any one of claims 1-4 for protecting the open trench tunnel water sealing structure of groundwater environment, feature exists In,
The vertical frozen soil sealing layer includes vertical freezing hole, and the diameter in the vertical freezing hole is 50~200 millimeters;It is described perpendicular It is 500~1000 millimeters to the spacing between freezing hole;And/or
The horizontal direction frozen soil sealing layer includes horizontal direction freezing hole, and the diameter of the horizontal direction freezing hole is 50~200 millimeters; Spacing between the horizontal direction freezing hole is 500~1000 millimeters;The horizontal direction freezing hole and tunnel floor panel structure foreign steamer Wide clear spacing is 200~800 millimeters.
7. a kind of construction of the open trench tunnel water sealing structure as claimed in any one of claims 1 to 6 for protecting groundwater environment Method, which is characterized in that including:
Constructing tunnel is divided into multiple construction sections;
In the excavation starting point of each construction section, construction shaft is set;
It is drilled down into vertical freezing hole from ground in the two sides of default tunnel open excavation foundation pit position, creeps into and freezes below tunnel floor Hole, the tripping in freezing pipe in freezing hole, the tripping in liquid supply pipe in the freezing pipe;
Refrigeration system is freezed in installation, will freeze refrigeration system and is connected respectively with thermometer hole, liquid supply pipe;
Freeze operation is carried out, vertical frozen soil sealing layer, horizontal direction frozen soil sealing layer are constructed;The vertical frozen soil sealing layer and level To the frozen soil sealing layer of frozen soil sealing layer building U-shaped;
After vertical frozen soil sealing layer, the thickness of horizontal direction frozen soil sealing layer and intensity reach preset requirement, frozen construction into Enter after safeguarding freezing period, layer-by-layer excavation pit;
Thermal insulation concrete is sprayed, tunnel lining structure is constructed.
8. construction method as claimed in claim 7, which is characterized in that the drilling of the freezing hole includes:
Determine freezing pipe, relief tube, the specification of liquid supply pipe, equipment of drilling;
Drilling machine platform is built, position is increased in the drilling machine platform setting layering;
Freezing hole aperture, the drilling mounting hole pipe of each freezing hole;
By the fixed drilling machine of freezing hole design orientation, freezing pipe is put into drilling, it is close to seal header joints after projected depth under freezing pipe Seal the gap of freezing pipe and orifice tube;Freezing pipe and freezing hole concentricity, freezing hole leak test pressure is in 0.7~1.0MPa;
The tripping in liquid supply pipe in freezing pipe, liquid supply pipe bottom end welding support, and outlet and circuit goat's horn are installed, and freeze pipe end Lid.
9. construction method as claimed in claim 7, which is characterized in that described to freeze in refrigeration system, outlet saline line is returned Pressure gauge, temperature sensor, control valve are respectively mounted in the saline line of road;And/or Brine Pipe outlet installation flowmeter;With/ Or, installing two valves of control freezing phase brine flow between brine distributing ring and frigo;And/or the eminence peace of saline line Put air valve;And/or refrigerant agent uses calcium chloride solution, specific gravity 1.265;And/or
Polystyrene foam plastics insulating layer, plastic film are set gradually outside the saline line;And/or freeze the steaming of unit Hair device and cryogenic pipe are kept the temperature with flex foam, and brine tank and salt water conduit tube are kept the temperature with polystyrol plastic foam plate.
10. such as the described in any item construction methods of claim 7-9, which is characterized in that the freeze operation includes:
In the case where adjusting pressure, temperature at any time, refrigeration system is freezed in operating;
In freezing process, timing detects brine temp, brine flow and frozen soil sealing layer spread scenarios;
It determines that horizontal direction frozen soil sealing layer has formed loop connecting structure, and reaches preset thickness;
Determine inside horizontal direction frozen soil sealing layer in non-frozen soil 2 meters or more without freezing water;
After being excavated in soil layer, determine that thickness, surface temperature and the deformation of horizontal direction frozen soil sealing layer reach preset requirement;
Enter maintenance freezing period after excavation of foundation pit;In maintenance freezing period, if frozen soil sealing layer expansion rate is more than preset value, frozen soil The super pre-value of the bearing capacity of sealing layer, stability improves brine temp then in the case where brine temp is not higher than -20 DEG C.
CN201610425630.2A 2016-06-16 2016-06-16 For protecting the open trench tunnel water sealing structure and construction method of groundwater environment CN105908765B (en)

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