CN211737181U - Push-pull type construction ventilation system for large underground water seal cave depot group - Google Patents
Push-pull type construction ventilation system for large underground water seal cave depot group Download PDFInfo
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- CN211737181U CN211737181U CN201820407324.0U CN201820407324U CN211737181U CN 211737181 U CN211737181 U CN 211737181U CN 201820407324 U CN201820407324 U CN 201820407324U CN 211737181 U CN211737181 U CN 211737181U
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Abstract
The utility model discloses a push-pull construction ventilation system for large underground water seal cave depot groups, which is characterized in that a process shaft and a ventilation shaft at two ends of a cave depot are communicated with a top layer in time to form an air flow loop; a full-jet fan arrangement structure is adopted, and vertical shafts at two ends of the cave depot are fully utilized to form 'front-pulling rear-pushing' push-pull ventilation; selecting the type and designing the ventilation through a jet fan; reasonably arranging a fan and an auxiliary ventilation facility; and optimizing the ventilation design by combining the field condition. The system ingeniously utilizes the ventilation vertical shafts and the process vertical shafts which are positioned at two sections of the cave depot, adopts a push-pull type ventilation mode based on a full-jet fan, and ingeniously avoids the phenomenon of air current channeling which is possibly formed by staggered communicated roadways and the like brought by the fact that the top layer is communicated after the top layer is communicated through the reasonable arrangement of ventilation facilities inside the cave depot, so that harmful substances generated on the working surface inside the cave depot are discharged out of the cave depot through the shortest path, the retention of foul gas in the construction environment is avoided, and the ventilation cost is minimized under the condition of ensuring the safety and comfort of the internal environment of the.
Description
Technical Field
The utility model belongs to the technical field of underground cavern architectural design construction, a large-scale underground cavern construction ventilation method is related to, and ventilation system is under construction in the lower floor's work progress in particular to secret water seal cave depot crowd.
Background
The large underground water-sealed cave depot or cave depot group has larger section and the area of the cave depot group is 400m2Above, about 2-3 times of common highway tunnels, the construction of an extra-large section is bound to be accompanied with the generation of a large amount of harmful substances such as dirty harmful gas, dust and the like, and due to the characteristic of the extra-large section, a layered construction method is usually adopted in a construction mode, namely, the excavation construction is divided into three layers of a top layer, a middle layer and a lower layer for sequential excavation. For the layered construction, the construction environment during the construction of each layer has great difference, the requirements on the ventilation effect and the ventilation measure and the arrangement have great technical influence, and for the large underground water seal cave depot, the construction ventilation problem during the construction is a major problem to be solved urgently, which relates to the health of field operating personnel, the construction safety and the construction efficiency improvement, and effective construction ventilation measures must be taken pertinently according to the construction characteristics.
For the middle-lower layer construction of large underground water-sealed cave depot and cave depot groups, the structure of the large underground water-sealed cave depot is complex, and the ventilation mode mainly refers to the tunnel ventilation mode at the current stage, namely, the single-end press-in mode of directly sending fresh air to an excavation working surface by using an air pipe and an axial flow fan and the two modes based on a parallel roadway are included, but the structure has obvious defects and limitation on the basis of the two ventilation modes because the underground cave depot and the tunnel have obvious difference in excavation cross-sectional area and tunnel arrangement form.
For single-head press-in ventilation, an axial flow fan directly sends fresh air to an excavation working face through an air pipe, pollutants are discharged through backflow, and when middle and lower layers of a large water-sealed cave depot group are constructed, the method has three problems that firstly, as the top layer of the cave depot is excavated, the fracture surface of the cave depot is enlarged by 2 times or even 3 times relative to the top layer, and at the moment, because of huge air volume demand caused by huge space, the requirement can be met only by configuring an ultrahigh-power axial flow fan, and the construction ventilation cost is greatly increased; secondly, the cross section area of the cave depot is larger, the single-head press-in type ventilation effect is weak, a large amount of fresh air flow loss is caused by the problems of zigzag and staggered roadways, air leakage of air pipes and the like, and the top layer of the cave depot is communicated, so that on one hand, most of the fresh air flow is very likely to directly flow out through the top layer, and pollution source items in the cave depot are polluted, namely the construction environment of the excavation working face is less influenced, the ventilation effect in the cave is poorer, and the reasonable utilization rate of ventilation machinery is low; finally, as the top layer is penetrated, the fresh air flow polluted by pollutants generated by excavation of the working face is likely to cause secondary pollution in the internal channeling of the cavern penetrating the top layer.
Therefore, during the top layer construction of the large underground water seal cave depot or the cave depot group, if the single-head press-in type ventilation that the axial flow fan adds the air pipe to directly send fresh air to the working face is adopted, once the construction is carried out on the second layer and the third layer, because the top layer of the main cavern is communicated, the construction of the single-head press-in type ventilation that the axial flow fan adds the air pipe is continuously adopted no matter the excavation area or the space arrangement form in the cave depot has great change relative to the top layer construction, and the construction ventilation in the construction process can not meet the requirement.
The tunnel type ventilation adopts a jet fan as power, utilizes a construction tunnel, and then directly sends fresh air to an excavation working surface through an air pipe by an axial flow fan arranged in a fresh air area. When constructing the middle and lower layers of a large water-sealed cave depot group, roadway type ventilation is adopted, which has two major problems, on one hand, the characteristics that a plurality of groups of caves are communicated with each other and the roadways are communicated with each other are adopted for the large underground water-sealed cave depot, and the like, if the network roadway type ventilation based on the air net formed in the cave depot is adopted, polluted air flow polluted by harmful substances discharged from a working surface in a single cave depot can flow into the adjacent cave depot along with the channels such as the communication and the like, so that secondary pollution is caused; on the other hand, for a complex cavern group, generally, a construction mode of parallel construction of a plurality of working surfaces is adopted due to the consideration of a construction period, at the moment, if roadway type ventilation is adopted, the discharge distance of foul gas inside the cavern is increased, the ventilation resistance inside the cavern is increased, so that the construction ventilation cost is increased, and at the moment, if pollutants among a plurality of caverns are accumulated, the risk of construction inside the cavern may be indirectly increased.
In conclusion, the large underground water seal cave depot or cave depot group has the characteristics of large section, layered excavation, intercommunication of a main cave and multiple roadways and the like, so that the traditional single-head press-in type or roadway type ventilation cannot meet the requirement in the construction process, and the major defects of high cost, difficult control, poor ventilation effect, secondary pollution and the like exist.
Disclosure of Invention
The utility model aims at providing a large-scale underground water seal cave depot or cave depot crowd push-pull construction ventilation system and ventilation method thereof to solve the ventilation problem of being under construction in large-scale underground water seal cave depot and the cave depot crowd work progress, solve this type cave depot top layer and link up the back, the construction ventilation effect that appears is poor in the middle and lower floor construction time ventilation process, ventilation engineering energy consumption big cost height and cave depot probably appear secondary pollution scheduling problem.
In order to solve the technical problem, the utility model provides a large-scale water seal cave depot crowd push-pull construction ventilation system in underground to realize through following technical scheme:
the utility model discloses at first, large-scale underground water seal cave depot crowd push-pull construction ventilation system, the cave depot crowd includes main hole, construction main tunnel and construction branch tunnel, its characterized in that: the two ends of the main tunnel are respectively provided with a ventilation vertical shaft and a process vertical shaft through excavation, and the top surfaces of the main tunnel and the construction main roadway are sequentially provided with jet fans at intervals to form a one-way shortest sewage air flow path which is formed by the ventilation vertical shaft as a fresh air inlet and the process vertical shaft as a foul gas outlet and flows through the holes and the roadways in a parallel mode.
The cave depot is composed of a single-channel main cave, and a ventilation vertical shaft and a process vertical shaft of the single-channel main cave structure are arranged at two ends of the main cave; a plurality of sets of jet flow fans are sequentially arranged on the top surfaces of the main tunnel and the construction main tunnel at intervals to form a shortest blow-down airflow path which is formed by air inlet of the ventilation vertical shaft and the construction main tunnel and air outlet of the process vertical shaft and flows through each tunnel and tunnel.
The other cave depot group consists of multi-channel main caves, and multi-channel main cave structures are communicated through construction branch roadways among the main caves, wherein the construction branch roadways are connecting channels which enter the main caves from the construction main laneways, and the construction main laneways are traffic channels which enter the main caves from the outside; the multi-channel main tunnel structure ensures that air inlet of the ventilation vertical shaft can be formed in each main tunnel, an independent air flow loop for air outlet of the process vertical shaft comprises at least one group of ventilation vertical shafts and at least one group of process vertical shafts, and the ventilation vertical shafts and the process vertical shafts are arranged at the end parts of the main tunnels or two adjacent main tunnels share one ventilation vertical shaft; a plurality of sets of jet flow fans are sequentially arranged on the top surfaces of the main holes and the construction main roadway at intervals to form a one-way shortest sewage air flow path which is formed by air inlet of the ventilation vertical shaft and the construction main roadway and air outlet of the process vertical shaft and is mutually independent among the main holes.
The construction branch roadway can be provided with an openable air valve. And a ventilation roadway and a flow dividing valve for supplying air to the multiple main holes are arranged at the inlet of the ventilation vertical shaft.
The ventilation system adopts a push-pull ventilation construction method; the method comprises the following steps:
(1) after the top layer is excavated, the excavation of the ventilation vertical shafts and the process vertical shafts at the two ends of the main tunnel is finished; or the top layer of the main tunnel, the ventilation vertical shafts at the two ends of the main tunnel and the process vertical shaft are excavated at the same time; ensuring that the ventilation vertical shaft and the process vertical shaft are communicated with the top layer of the main tunnel to form an air current loop when the middle layer and the lower layer of the main tunnel are constructed;
(2) jet fans are arranged in the cave depot at intervals, a push-pull construction ventilation mode is adopted, a ventilation vertical shaft at one end of the main cave is used as a fresh air inlet, and a process vertical shaft at the other end of the main cave is used as a foul air outlet, so that one-way air flow is formed.
The push-pull type construction ventilation mode is different from the existing roadway type and single-head press-in type, namely an axial flow fan is abandoned, a jet flow fan is arranged in a main tunnel, a certain positive pressure difference is formed between the interior of the main tunnel and the external environment connected through a process vertical shaft, a certain suction force is formed at the process vertical shaft mouth, polluted air flow carrying harmful substances such as harmful gas, smoke dust and the like generated in the construction of a working surface is pulled outwards through the process vertical shaft, a certain negative pressure difference is formed between the interior of the main tunnel and the external environment connected through the ventilation vertical shaft, so that a thrust force is formed at the ventilation vertical shaft mouth, fresh air is pushed into the interior of a cave depot through the ventilation vertical shaft, a push-pull type of pulling forwards and pushing backwards is formed, the polluted air flow in the cave depot is discharged out of the cave depot through the shortest path, and the safety and comfort of the construction environment in the;
the cave depot group consists of a single-channel main cave or a multi-channel main cave group.
The ventilation vertical shaft and the process vertical shaft of the single-channel main tunnel structure are arranged at two ends of the main tunnel; a plurality of sets of jet flow fans are arranged on the top surfaces of the main hole and the construction main roadway to form a shortest blow-down air flow path which is formed by air inlet of the ventilation vertical shaft and the construction main roadway, air outlet of the process vertical shaft and flow through each hole and roadway.
The multi-channel main tunnel structure is communicated through construction branch tunnels among the main tunnels, wherein the construction branch tunnels enter connecting channels among the main tunnels from the construction main tunnels, the construction main tunnels are main traffic channels outside and enter the main tunnels, the multi-channel main tunnel structure ensures that ventilation vertical shaft air inlet can be formed in each single-channel main tunnel, an independent air flow loop for air outlet of the process vertical shaft comprises at least one group of ventilation vertical shafts and at least one group of process vertical shafts, the ventilation vertical shafts and the process vertical shafts are arranged at the end parts of the main tunnels, and two adjacent single-channel main tunnels can share one ventilation vertical shaft according to conditions; a plurality of sets of jet flow fans are arranged on the top surfaces of the main holes and the construction main roadway to form a one-way shortest sewage air flow path which is formed by air inlet of the ventilation vertical shaft and the construction main roadway and air outlet of the process vertical shaft and is mutually independent among the main holes.
In the multichannel main tunnel structure, when the construction branch tunnel of each main tunnel of UNICOM sets up many in parallel, the accessible sets up open and close blast gate in the construction branch tunnel and adjusts the air current flow direction, forms ventilation shaft and construction main tunnel air inlet, technology shaft air-out, the one-way shortest blowdown blast current route of mutual independence between each main tunnel.
(3) Selecting and arranging jet fans, calculating the air quantity required by each ventilation factor according to the air quantity calculation theory of tunnel construction ventilation design, taking the maximum value of the calculated result of the air quantity required as the air quantity required by excavation design of a cave depot, calculating corresponding air pressure according to the air quantity required by design, and selecting and allocating the type of the fans and the quantity of the configured fans according to the air quantity required by design;
according to the characteristics of large section and small resistance of the cave depot, a fan is selected to abandon a high-power and high-energy-consumption axial flow fan, a low-energy-consumption and low-power jet flow fan is adopted, and the fan is corrosion-resistant and moisture-proof.
According to the tunnel construction ventilation design air quantity calculation theory, the fan number calculation is divided into three steps of calculating the design air quantity, calculating the ventilation resistance inside the cave depot and determining the fan number:
the design air demand calculation firstly respectively calculates the fresh air quantity required by constructors, the fresh air quantity required by diluting the waste gas of the internal combustion engine in the cave depot, the air quantity required by effective dust exhaust in the cave depot and the air quantity required by diluting and blasting the waste gas in the cave depot, and finally, the maximum value of the calculation result of each air demand is the design air demand, and the specific calculation formula is as follows:
Qr＝vrm
Qs＝Hs·qs·as+HD·qD·aD
Qv＝vsoot·A
Qxue＝max(Qv,Qs,Qb,Qr)
wherein Q isrAir quantity required for constructors in cave depots, vrThe fresh air quantity required by each person in the cave depot, the maximum number of people working in the cave depot m at the same time, and QbBlasting smoke exhaust air quantity, G simultaneous blasting explosive quantity (kg), A tunnel excavation section area (m)3),L0Length (m), Q) of ventilationsDilution of the air demand H of the exhaust gases from the operation of internal combustion enginessTotal rated power (kW), q of machines of the slag loader typesAir volume per rated power of slag loader class [ m ]3/(min·kw)]，asMechanical working efficiency of loaders, QvDust-removing air-quantity requirement v inside cave depotsootMinimum allowable dust wind speed.
Calculating the ventilation resistance inside the cave depot, including on-way resistance generated by the contact of the wind flow and the wall surface and local resistance generated by the local change of the section form in the cave depot due to the wind flow:
the on-way resistance generated by the contact of the wind flow and the wall surface can be calculated according to the following formula:
wherein h isfThe on-way resistance generated by wind current in the cave depot and the wall surface of the cave depot, the length of a section calculated by L, the hydraulic diameter of the fracture surface of the cave depot, and the design wind speed of each section in v, i.e. the minimum dust exhaust wind speed, the volume weight of the air in rho cave depot and the on-way resistance coefficient of the wall surface of the lambda cave depot can be calculated according to the hydraulic diameter in each cave segment and the roughness of the wall surface of the cave segment, i.e. the on-way resistance is calculated according to the hydraulic diameter in each cave segment and
the local resistance of the wind current due to local changes of the shape of the sections in the cavern can be calculated according to the following formula:
wherein, the local resistance coefficient under different conditions in the xi cave library can be changed by the ratio of the change of the sectional area of the local change region
And the hole section local turning angle alpha, the turning radius R and the section hydraulic diameter d are calculated, wherein when the section area is changed
Xi 0.008 alpha when the section is partially bent0.75/(R/d)0.8And the remaining symbols are the same as above.
The natural wind direction generated by the through of the vertical shaft can be divided into two different situations of resistance and power due to the natural wind according to the calculation of the number of jet flow fans inside the cave depot:
when the natural wind power in the cave depot is opposite to the sewage discharge direction, namely the natural wind power is resistance, the arrangement quantity of the jet flow fans can be calculated according to the following formula:
wherein h ismNatural wind power, can be selected from local resistance coefficient xi of vertical shaft inleteCoefficient of on-way resistance λrWind velocity v caused by natural windn(for specific calculation, see the rules for designing ventilation of road tunnels), etc., namely PjThe pressure of the jet fan is increased according to the outlet wind speed v of the jet fanjAnd the outlet area A of the jet flow fanjCalculating the reduction coefficient eta of the friction resistance loss of the position of the fan, namely
When the natural wind power in the cave depot is the same as the sewage discharge direction, namely the natural wind power is the power, the arrangement quantity of the jet flow fans can be calculated according to the following formula:
wherein, each symbol has the same meaning as above.
(4) Arranging and installing jet fans and auxiliary facilities, and selecting the arrangement positions, the arrangement quantity and the opening condition of the jet fans and arranging other ventilation auxiliary facilities such as air valves according to the field requirements by combining the internal construction environment and the construction condition of the cave depot so as to ensure that the functions of the fans are fully exerted, the fans are not damaged and the air flow in the cave is not subjected to cross flow;
the arrangement of the fan and the auxiliary facilities mainly comprises three parts of contents, namely fan installation position selection, fan arrangement and arrangement number adjustment in the cave depot and other ventilation auxiliary facilities arrangement:
due to the complex internal environment of the underground cave depot, the fan is arranged at a higher position of drying on the principle that the fan is ensured to fully play a role and not to be damaged when the fan mounting position is selected, so that the influence of moist air, dust and blasting seal flying stones on the efficiency of the fan and even the damage of the fan are avoided;
the principle of partial arrangement and opening number adjustment of fans in the cave depot is to ensure that the air quantity in the cave meets the requirement, the fan functions are fully exerted and the air flow in the cave does not cross flow, the fans are intensively arranged at the inlet of a ventilation shaft in the cave depot to form larger negative pressure and ensure that the sucked fresh air meets the air quantity requirement in the cave depot, the fans are dispersedly arranged at other places to overcome the internal resistance of the cave depot and ensure that the air speed in the cave is stable and reasonable, meanwhile, the fans are arranged in a construction main roadway, the air flow direction meets the requirement that the fresh air flow flows into the main cave depot from a construction branch roadway, the air flows of all main caves are mutually independent, and when the number of the opened fans enters the lower layer construction, the air quantity required in the cave depot is increased due to the increase of the section, and at the moment, jet flow fans are opened more or jet flow fans are additionally arranged according to the;
the other ventilation auxiliary facilities are arranged, namely air valve arrangement, and the air valve arrangement is mainly characterized in that when the number of construction branch tunnels between the main caverns is more than two, the construction branch tunnels are too many, the air net between the multi-channel main caverns is complex, and the air flow is difficult to control, so that the air valve can be arranged on the construction branch tunnels left by the top layer construction for plugging, the pollutant channeling phenomenon caused by the complex air net is prevented, the pollutants are prevented from being retained in the caverns, and the pollutants are discharged out of the main caverns through the shortest path.
(5) On the premise of ensuring the safety and comfort of the internal environment of the cave depot, the number of ventilation vertical shafts is reduced according to the field construction conditions by combining the actual conditions of the cave depot and on the basis of the condition that a push-pull basic ventilation mode is not changed, namely, a ventilation vertical shaft scheme shared by two main holes is adopted, and air supply is carried out on each main hole through a corresponding ventilation roadway.
When a large water-sealed cave depot group multi-channel main cave is in a condition, when a ventilation vertical shaft is difficult to set on site, the number of the ventilation vertical shafts can be reduced, on the basis of the condition that a push-pull basic ventilation mode is not changed, the ventilation vertical shaft is used for supplying air by sharing one ventilation vertical shaft, wherein the ventilation vertical shaft is communicated with two main caves through a ventilation tunnel, and meanwhile, in order to ensure reasonable air distribution between the two main caves, a flow dividing valve is additionally arranged at the joint of the ventilation vertical shaft and the main cave ventilation tunnel.
Compared with the prior art, the beneficial effects of the utility model are that:
the characteristics of large section and small resistance of a water-sealed cave depot are fully utilized, process vertical shafts and ventilation vertical shafts at two ends of the cave depot are skillfully utilized, a high-power and high-energy-consumption axial flow fan is abandoned, a low-power and corrosion-resistant jet flow fan is preferably selected, the number and arrangement positions of the fans are reasonably calculated, a push-pull ventilation mode of 'pulling forward and pushing backward' is adopted, polluted wind flow is directly discharged out of the cave depot through the shortest path, the ventilation effect is better than that of the traditional method, the environment in the cave depot is good, the characteristics of the cave depot are reasonably exerted under the condition that the safety and comfort of the construction environment in the cave are ensured, and;
the jet flow fan is reasonably arranged in the construction main roadway, so that the situation that an equal wind net loop is formed due to the fact that the top layer is communicated is ingeniously avoided, dirty air is discharged out of a tunnel through a vertical shaft in the shortest path, polluted wind flow is effectively prevented from being retained inside the tunnel or from channeling among different tunnels, secondary pollution is prevented, a safe and comfortable construction environment is provided for the parallel construction of multiple working faces of a tunnel group, the construction efficiency is indirectly improved, and the construction period is saved;
according to the field situation, ventilation facilities such as a fan and an air valve are reasonably arranged, and meanwhile, a ventilation vertical shaft is reasonably arranged by combining the construction field conditions, so that the utilization maximization of the ventilation facilities in the cave depot is achieved, the optimization of the construction ventilation environment under the construction conditions of frequent change in the cave is ensured, and the cost is minimized.
Drawings
FIG. 1 is a schematic cross-sectional view of a large underground water-sealed cave depot for layered construction;
FIGS. 2 to 4 are schematic longitudinal sectional views of the layered construction of the large-scale underground water seal cave depot;
FIG. 5 is a schematic view of one-end press-in construction ventilation;
FIG. 6 is a schematic illustration of roadway construction ventilation;
FIG. 7 is a schematic view of a push-pull type ventilation longitudinal section in middle layer construction of a large water seal cave depot;
FIG. 8 is a schematic view of a push-pull type ventilation horizontal plane in the middle layer construction of a large water seal cave depot;
fig. 9 is a plan view of a ventilation system of a push-pull ventilation shared ventilation shaft in middle layer construction of a large water seal cave depot when the shaft is difficult to arrange in the middle layer construction.
FIG. 10 is a schematic view of a push-pull type ventilation vertical section in the lower layer construction of a large water seal cave depot;
FIG. 11 is a schematic view of a push-pull type ventilation horizontal plane for the lower layer construction of a large water seal cave depot;
FIG. 12 is a schematic plan view of a ventilation system of a push-pull ventilation shared ventilation shaft for middle-floor construction in a large water seal cave depot when the shaft is difficult to arrange in the construction of the lower floor;
FIG. 13 is a schematic diagram showing the change of the main pollutant CO at the front end 15m of the working face of the cavern after blasting along with time.
The labels in the figure are: 1-main hole top layer, 2-main hole middle layer, 3-main hole lower layer, 4-main hole, 5-ventilation shaft, 6-process shaft, 7-jet fan, 8-construction main tunnel, 9-construction branch tunnel, 10-axial flow fan, 11-air pipe, 12-blocking air valve, 13-diversion air valve, 14-ventilation tunnel, A is excavation working face, B is dirty air, and C is fresh air.
Detailed Description
The present invention is described in detail below by way of examples, which are only used for further illustration of the present invention, and the limitation of the protection scope of the present invention is not understood, and some non-essential improvements and adjustments made by those skilled in the art according to the contents of the present invention also belong to the protection scope of the present invention.
With reference to the attached drawings.
As shown in fig. 7 to 12, in the present embodiment, the process shaft 6 and the ventilation shaft 5 are respectively located at two end portions of the main cave 4 of the cave depot, and the construction process of the middle floor 2 and the lower floor 3 of the cave depot is taken as an example for explanation, the ventilation shaft 5 is taken as a fresh air inlet, and the process shaft 6 is taken as a foul air outlet in the cave.
The push-pull construction ventilation method for the construction of the underground large water-sealed cave depot group comprises the following steps:
(1) after the top layer 1 is excavated, the excavation of the ventilation shafts 5 and the process shafts 6 at the two ends of the main tunnel 4 is immediately finished, or the ventilation shafts 5 and the process shafts 6 at the two ends of the main tunnel 4 and the top layer 1 of the main tunnel are simultaneously excavated, so that the shafts are ensured to be communicated with the top layer of the cave depot during the construction of the lower layer in the cave depot, and an air flow loop is formed;
(2) as shown in fig. 5, based on the favorable condition of the penetration of the top layer and the vertical shaft of the cave depot, a high-power axial flow fan is abandoned, instead, a jet flow fan 7 is arranged in the main cave 4, a push-pull construction ventilation mode is adopted, the ventilation vertical shaft 5 at one section of the cave depot is used as a fresh air inlet, and the process vertical shaft 6 at the other section is used as a foul air outlet, so that a shortest wind flow loop is formed;
(3) selecting and arranging jet fans, calculating the air quantity required by each ventilation factor according to the air quantity calculation theory of tunnel construction ventilation design, taking the maximum value of the calculated result of the air quantity required as the air quantity required by excavation design of a cave depot, calculating corresponding air pressure according to the air quantity required by design, and selecting and allocating the type of the fans and the quantity of the configured fans according to the air quantity required by design;
(4) arranging and installing jet fans and auxiliary facilities, and selecting the arrangement positions, the arrangement quantity and the opening condition of the jet fans and arranging other ventilation auxiliary facilities such as air valves according to the field requirements by combining the internal construction environment and the construction condition of the cave depot so as to ensure that the functions of the fans are fully exerted, the fans are not damaged and the air flow in the cave is not subjected to cross flow;
(5) on the premise of ensuring the safety and comfort of the internal environment of the cave depot, the number of ventilation vertical shafts is reduced according to the site construction conditions by combining the actual conditions of the cave depot and on the basis of the condition that a push-pull basic ventilation mode is not changed, and air supply is carried out on each main cave through corresponding ventilation facilities.
As shown in fig. 7 and 8, in this embodiment, the ventilation shafts 5 and the process shafts 6 are respectively disposed at two ends of the main tunnel 4, and when the cave depot enters the middle-lower layer construction, the excavation working surface a is respectively located at the middle layer 2 or the lower layer 3, so as to ensure that the two sections of shafts form a passage with the main tunnel, and form a wind flow loop in the main tunnel 4. Meanwhile, an axial flow fan is abandoned, a certain positive pressure difference is formed between the interior of the main hole 4 and the external environment connected through the process vertical shaft 6 by arranging jet flow fans 7 at intervals in the main hole 4, a pollution wind flow similar to the pollution wind flow carrying harmful substances such as harmful gas, smoke dust and the like generated by the construction of a working surface is formed, the pollution wind flow is pulled out outwards through the process vertical shaft, a certain negative pressure difference is formed between the main hole 4 and the external environment connected through the ventilation vertical shaft 5, a form similar to the form that the ventilation vertical shaft 5 pushes fresh air into the interior of the cave depot, and therefore a push-pull form of 'front pulling and rear pushing' is formed, the pollution wind flow in the cave depot is discharged out of the cave depot through the shortest path, and the safety and comfort of the construction environment in the;
in this embodiment, the section of the cave depot is largely divided into 1, 2 and 3 three layers of construction, and this time when the middle layer 2 and the lower layer 3 are constructed, the basic construction ventilation system control idea is as follows: when constructing 2 layers, the ventilation schematic diagram is shown in figures 7-8, when constructing 3 layers, the ventilation schematic diagram is shown in figures 10-11, two main holes 4 are in a group, the two main holes are communicated through a construction branch tunnel 9 and a construction main tunnel 8, a certain amount of jet fan groups 7 are arranged in the main holes 4 and the construction main tunnel 8, fresh air C is provided for the construction of a working face A through a construction ventilation shaft 5, dirty air B generated by the working face A is discharged out of a main hole warehouse 4 through a process shaft 6, simultaneously, when constructing a lower layer 3, as shown in figure 11, if the number of the construction branch tunnels 9 is too large, an air valve 12 can be arranged to control the ventilation of the tunnels, and the tunnel can also be combined with site conditions, when constructing the middle layer 2, a construction ventilation system as shown in figure 9 is adopted, when constructing the lower layer 3, a ventilation system as shown in figure 12 is adopted, namely, two main holes 4 share one ventilation shaft 5, and other ventilation systems 14 and a shunt air valve 13 are arranged to control the air distribution, more specifically, the following is a detailed description.
In the embodiment, when the fan is selected, a high-power and high-energy-consumption axial flow fan is abandoned, a low-energy-consumption and low-power jet fan is adopted, the power of the jet fan is 2 multiplied by 11kw, dust and smoke generated by blasting are contained in the air in the underground water sealed tunnel, and the air is generally moist due to the water sealing characteristic, so that the fan is a corrosion-resistant and moisture-proof fan.
According to the design theory of ventilation air demand of tunnel construction, the calculation of the number of fans is divided into three steps of calculating the design air demand, calculating the air pressure in a cave depot and determining the number of fans:
the design air demand calculation firstly respectively calculates the fresh air quantity required by constructors, the fresh air quantity required by diluting the waste gas of the internal combustion engine in the cave depot, the air quantity required by effective dust exhaust in the cave depot and the air quantity required by diluting and blasting the waste gas in the cave depot, and finally, the maximum value of the calculation result of each air demand is the design air demand, and the specific calculation formula is as follows:
Qr＝vrm
Qs＝Hs·qs·as+HD·qD·aD
Qv＝vsoot·A
Qxue＝max(Qv,Qs,Qb,Qr)
wherein Q isrAir quantity required for constructors in cave depots, vrThe fresh air quantity required by each person in the cave depot, the maximum number of people working in the cave depot m at the same time, and QbBlasting smoke exhaust air quantity, G simultaneous blasting explosive quantity (kg), A tunnel excavation section area (m)3),L0Length (m), Q) of ventilationsDilution of the air demand H of the exhaust gases from the operation of internal combustion enginessTotal rated power (kW), q of machines of the slag loader typesAir volume per rated power of slag loader class [ m ]3/(min·kw)]，asMechanical working efficiency of loaders, QvDust-removing air-quantity requirement v inside cave depotsootMinimum allowable dust wind speed.
In this embodiment, the calculated wind demand for the middle layer 2 and the lower layer 3 is the dust-exhausting wind demand Q in the cave depotvI.e. Qv＝vsoot·A；
Calculating the ventilation resistance inside the cave depot, including on-way resistance generated by the contact of the wind flow and the wall surface and local resistance generated by the local change of the section form in the cave depot due to the wind flow:
the on-way resistance generated by the contact of the wind flow and the wall surface can be calculated according to the following formula:
wherein h isfThe on-way resistance generated by wind current in the cave depot and the wall surface of the cave depot, the length of a section calculated by L, the hydraulic diameter of the fracture surface of the cave depot, and the design wind speed of each section in v, i.e. the minimum dust exhaust wind speed, the volume weight of the air in rho cave depot and the on-way resistance coefficient of the wall surface of the lambda cave depot can be calculated according to the hydraulic diameter in each cave segment and the roughness of the wall surface of the cave segment, i.e. the on-way resistance is calculated according to the hydraulic diameter in each cave segment and
the local resistance of wind current caused by local change of the section shape in the tunnel can be calculated according to the following formula
Wherein, the local resistance coefficient under different conditions in the xi cave library can be changed by the ratio of the change of the sectional area of the local change region
And the hole section local turning angle alpha, the turning radius R and the section hydraulic diameter d are calculated, wherein when the section area is changed
Xi 0.008 alpha when the section is partially bent0.75/(R/d)0.8And the remaining symbols are the same as above.
The natural wind direction generated by the through of the vertical shaft can be divided into two different situations of resistance and power due to the natural wind according to the calculation of the number of jet flow fans inside the cave depot:
according to the practical situation, when the natural wind power in the cave depot is opposite to the sewage discharge direction, namely when the natural wind power is resistance, the arrangement quantity of the jet fans can be calculated according to the following formula:
wherein h ismNatural wind power, can be selected from local resistance coefficient xi of vertical shaft inleteCoefficient of on-way resistance λrWind velocity v caused by natural windn(for specific calculation, see the rules for designing ventilation of road tunnels), etc., namely PjThe pressure of the jet fan is increased according to the outlet wind speed v of the jet fanjAnd the outlet area A of the jet flow fanjCalculating the reduction coefficient eta of the friction resistance loss of the position of the fan, namely
According to the practical situation, when the natural wind power in the cave depot is the same as the sewage discharge direction, namely the natural wind power is power, the arrangement quantity of the jet fans can be calculated according to the following formula:
wherein, each symbol has the same meaning as above.
In this embodiment, the natural wind direction is the same as the sewage discharge direction, so the fan calculation is adopted
And calculating, wherein 5 jet flow fans are respectively arranged in each main hole when the middle layer 2 is constructed, and 6 jet flow fans are respectively arranged in each main hole when the lower layer 3 is constructed.
In the embodiment, the jet fans 7 are uniformly distributed at the higher dry position, and special dustproof fans are adopted and are arranged at the drier position in the cave storage, so that the influence of damp air, dust and blasting flying stones on the fan efficiency and even damage of the fan are avoided, meanwhile, the fans at the positions, away from the ventilation shaft inlet, in the cave storage are intensively distributed to form larger negative pressure, the sucked fresh air meets the requirement of the air quantity in the cave storage, the fans at the positions, away from the ventilation shaft inlet, in the cave storage are dispersedly distributed to overcome the internal resistance of the cave storage, and the air speed in the cave storage is ensured to,
when constructing the middle level of the cave depot in this embodiment, 3 groups of jet fans 7 are arranged at the entrance, and 2 groups of fans are arranged at other positions, and meanwhile, as shown in fig. 9, when entering the cave depot lower layer 3 for construction, the increase of the required air volume inside the cave depot due to the increase of the section is brought, and 1 group of jet fans 7 are additionally arranged in the area close to the ventilation shaft.
In this embodiment, as shown in fig. 8, when the middle layer 2 is constructed, after the top layer construction is completed, the two main holes 4 are communicated with each other through the construction main roadway 8 and the construction branch roadway 9, at this time, four jet fans 7 are disposed in the construction main roadway 80, fresh air C is supplemented into the main hole 4 through the construction branch tunnel 9 to avoid forming an air net, so that the dirty air B generated by the construction of the working face A does not flow in the cave depot, directly discharged out of the cave depot through the process vertical shaft 6 to ensure that pollutants are not retained in the cave depot and discharged out of the main cave depot through the shortest path, meanwhile, when the lower layer 3 is constructed, as shown in fig. 11, the basic ventilation mode is unchanged, only the number of the construction branch roadways 9 exceeds two groups, so in order to prevent the formation of a complex wind net, an air valve 12 is arranged in the top construction branch roadway 9 to ensure the safety and reliability of the internal construction environment of the cave depot and facilitate the ventilation control of the internal construction of the cave depot.
In this embodiment, due to the limitation of site conditions, the ventilation shaft 5 is difficult to set, so that the middle layer 2 is constructed as shown in fig. 9, the lower layer 3 is constructed as shown in fig. 12, two main holes 4 are adopted to supply air through the single ventilation shaft 5, the ventilation shaft 5 is communicated with the main holes 4 through the ventilation tunnel 14, the two different main holes 4 are respectively supplied with air, and the diversion valve 13 is arranged at the ventilation shaft 5 and the joint between the ventilation shaft 5 and the ventilation tunnel 14, so as to ensure the reasonable distribution of the air volume of each hole.
The push-pull ventilation described in this embodiment is now compared with the single-head press-in type to illustrate the great energy saving and advantages of this solution.
In the single-head forced ventilation method, as shown in fig. 5, fresh air C is directly supplied to the working surface a by the axial flow fan 10 and the air duct 11, and dirty air B is forced out.
The air quantity required by middle layer construction of the cave depot is 3384m3/min, if a single-head press-in type axial flow fan is adopted, SDF (B) -6-No17 is adopted, the power is 320kw, if a push-pull type jet flow fan is adopted, SDS (R) -No11.2 is adopted, the power is 22kw, and the construction period is excavated for 5 months according to each layer, the energy consumption of the single-head press-in type and push-pull type construction ventilation process is as follows:
it is thus clear that the utility model discloses a relative tradition is single to be pressed into can reduce great energy loss, saves a large amount of ventilation costs, has obvious superiority.
In this embodiment, after the push-pull type construction ventilation manner is adopted, since the pollutants generated on the working surface are directly discharged out of the cavern through the shortest path, as shown in fig. 13, fig. 13 is a schematic diagram of a time-varying curve of the main pollutants CO at 15m in front of the working surface of the cavern after blasting, in the diagram, the abscissa is ventilation time in unit: s (seconds); the ordinate is CO concentration, in units: ppm; after blasting, the concentration of main polluted CO in a construction area 15m from the front end of a working face A in the cave depot is rapidly reduced, namely the concentration is reduced to 100ppm which can be safely constructed in an approach field within 6min, the time is about 9min earlier than 15min specified by the current stage specification, meanwhile, the concentration is rapidly reduced to 24ppm which can be retained in the cave for a long time after 14min of ventilation, the time is about 16min earlier than 30min specified by the specification, the construction ventilation effect is obvious, and the internal environment of the cave depot can be safely and comfortably achieved within a short time after blasting.
The ventilation method ingeniously utilizes the ventilation vertical shafts and the process vertical shafts which are positioned at two sections of the cave depot, adopts a push-pull type ventilation mode based on a full-jet fan, and ingeniously avoids the phenomenon of air flow channeling which is possibly formed by staggered communicated roadways and the like caused by the fact that the top layer is communicated after the top layer is communicated through the reasonable arrangement of ventilation facilities in the cave depot, so that harmful substances generated on the working surface in the cave depot are discharged out of the cave depot through the shortest path, the retention of dirty gas in the construction environment is avoided, and the lowest ventilation cost is achieved under the condition that the safety and the comfort of the internal environment of the.
Claims (5)
1. The utility model provides a large-scale underground water seal cave depot crowd push-pull type construction ventilation system, cave depot crowd includes main hole, construction main roadway and construction branch tunnel, its characterized in that: the two ends of the main tunnel are respectively provided with a ventilation vertical shaft and a process vertical shaft through excavation, and the top surfaces of the main tunnel and the construction main roadway are sequentially provided with jet fans at intervals to form a one-way shortest sewage air flow path which is formed by the ventilation vertical shaft as a fresh air inlet and the process vertical shaft as a foul gas outlet and flows through the holes and the roadways in a parallel mode.
2. The push-pull construction ventilation system for large underground water-seal cave depot group according to claim 1, characterized in that: the cave depot is composed of a single-channel main cave, and a ventilation vertical shaft and a process vertical shaft of the single-channel main cave structure are arranged at two ends of the main cave; a plurality of sets of jet flow fans are sequentially arranged on the top surfaces of the main tunnel and the construction main tunnel at intervals to form a shortest blow-down airflow path which is formed by air inlet of the ventilation vertical shaft and the construction main tunnel and air outlet of the process vertical shaft and flows through each tunnel and tunnel.
3. The push-pull construction ventilation system for large underground water-seal cave depot group according to claim 1, characterized in that: the cave depot group consists of multi-channel main caves, and multi-channel main cave structures are communicated through construction branch roadways among the main caves, wherein the construction branch roadways are connecting channels which enter the main caves from the construction main laneways, and the construction main laneways are traffic channels which enter the main caves from the outside; the multi-channel main tunnel structure ensures that air inlet of the ventilation vertical shaft can be formed in each main tunnel, an independent air flow loop for air outlet of the process vertical shaft comprises at least one group of ventilation vertical shafts and at least one group of process vertical shafts, and the ventilation vertical shafts and the process vertical shafts are arranged at the end parts of the main tunnels or two adjacent main tunnels share one ventilation vertical shaft; a plurality of sets of jet flow fans are sequentially arranged on the top surfaces of the main holes and the construction main roadway at intervals to form a one-way shortest sewage air flow path which is formed by air inlet of the ventilation vertical shaft and the construction main roadway and air outlet of the process vertical shaft and is mutually independent among the main holes.
4. The push-pull construction ventilation system for large underground water-seal cave depot group according to claim 3, characterized in that: the construction branch roadway can be provided with an openable air valve.
5. The push-pull construction ventilation system for large underground water-seal cave depot group according to claim 3, characterized in that: and a ventilation roadway and a flow divider valve for supplying air to the multiple main holes are arranged at the inlet of the ventilation vertical shaft.
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| CN201820407324.0U CN211737181U (en) | 2018-03-23 | 2018-03-23 | Push-pull type construction ventilation system for large underground water seal cave depot group |
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