阅读说明：本技术 一种倒台阶式竖井结构及其井喷减免方法 (Inverted step type vertical shaft structure and blowout reducing and avoiding method thereof ) 是由 王芳芳 吴时强 吴修锋 戴江玉 高昂 杨倩倩 张宇 黄标 王小东 崔鹏飞 徐鹏 于 2020-05-13 设计创作，主要内容包括：本发明涉及一种倒台阶式竖井结构及其井喷减免方法,竖井设置于地下管道顶部,连通地下管道与地面,井盖设置于竖井顶部。所述竖井一侧外形为台阶状,并沿洞口轴线镜像,台阶宽度大于地下管道宽度,可整体成型亦可组装。所述竖井台阶第一级台阶与地面齐平,中心挖出一圆柱体,为竖井口；最后一级台阶与地下管道顶部衔接,中间台阶坡度为30°至60°为；台阶上方回填料与地面齐平。本发明坦化形成井喷的驱动压力差值,井盖设置通气孔连通地下管道与地面大气,平衡竖井和地下管道内的非恒定气压,提前平衡管道内气压,坦化形成井喷现象的驱动压力差极值,有效抑制井喷发生条件形成。(The invention relates to an inverted step type vertical shaft structure and a blowout relief method thereof. One side of the vertical shaft is step-shaped and is mirrored along the axis of the opening, and the step width is larger than that of the underground pipeline, so that the vertical shaft can be integrally formed and can also be assembled. The first step of the vertical shaft step is flush with the ground, and a cylinder is dug out from the center and is a vertical shaft opening; the last step is connected with the top of the underground pipeline, and the gradient of the middle step is 30-60 degrees; the backfill above the step is flush with the ground. The well cover is provided with the vent holes to communicate the underground pipeline and the ground atmosphere, so that the non-constant air pressure in the vertical shaft and the underground pipeline is balanced, the air pressure in the pipeline is balanced in advance, the driving pressure difference extreme value of the well blowout phenomenon is formed by means of planarization, and the formation of the well blowout occurrence condition is effectively inhibited.)

1. An inverted step type shaft structure, characterized by comprising: set up in the shaft cavity at underground piping top, set up in the well lid at shaft top, and set up the multistage step of falling of shaft both sides.

2. The inverted stepped shaft structure according to claim 1, wherein: the multistage inverted steps are mirrored along the axis of the opening of the vertical shaft, and the wall surface of the vertical shaft forms a herringbone ladder shape and is supported above the underground pipeline.

3. The inverted stepped shaft structure according to claim 2, wherein: the first step of the multi-stage inverted steps is flush with the ground, and a round or square hollow body is dug out in the center and is a vertical well mouth; the last step is connected with the top of the underground pipeline, the integral slope angle of the step is 30-60 degrees, and the step number is 3-10; and the backfill above the step is flush with the ground.

4. The inverted stepped shaft structure according to claim 1, wherein: the manhole cover is an inverted frustum body, the top of the manhole cover is flush with the ground and is horizontally placed, the manhole cover component comprises a lifting handle, a manhole cover support and a limiting measure, the manhole cover is fixed on the ground through the manhole cover support, a manhole cover support hinge is fixed on the manhole cover support, a manhole cover rib plate is arranged on the outer edge of the manhole cover in a radiation mode from the center, a manhole cover rib plate connected with the manhole cover support is provided with an S-shaped rib plate track, and the manhole cover support hinge slides in the S-shaped rib plate track; the limiting measures comprise a limiting soft rope, a soft rope hook and a soft rope support.

5. The inverted stepped shaft structure according to claim 4, wherein: the well cover is provided with air vents and air vent middle holes, and the air vents are communicated with the underground pipeline and the ground atmosphere; the vent holes are distributed in an array mode, and the aperture is 2 cm-5 cm; the mesopore of ventilating is located the well lid center, and the aperture is greater than the air vent, for 1/10~1/3 of well lid diameter, the mesopore of ventilating sets up the top cap, and this top cap one end hinge is propped up, and in the draw-in groove was blocked to the other end, the top cap was opened automatically under the predetermined pressure difference.

6. The inverted stepped shaft structure according to claim 4, wherein: the limiting soft rope is arranged at the bottom of a well lid rib plate at the other end of the well lid support, the limiting soft rope is temporarily fixed on the soft rope support through a movable hook, and the maximum opening range of the limiting well lid is 15-45 degrees when the length of the soft rope is fully expanded; the lifting handle is arranged on the upper side of the flat plate of the well lid structure corresponding to the soft rope support.

7. A blowout abatement method for an inverted stepped shaft structure according to any one of claims 1 to 6, comprising for different scenarios:

scenario 1, multistage gas pressure release: the underground pipeline water flow is connected with a vertical shaft in a transition mode by adopting a multi-stage inverted step body type with a suddenly expanded top, the inverted step body type is favorable for gas overflow and air bag release in the pipeline, gas is not easily involved in the top when the flow is reversed, and the existing trapped air bag at the top of a main flow is stably released from the mechanism and the formation of a new large air bag is inhibited, so that the multi-stage inverted step body type can achieve the effect of multi-stage release of non-constant gas pressure, and pressure extreme values with time continuity and space concentration are dispersed into discontinuous pressure extreme values with multiple points in space, thereby inhibiting the formation of necessary pressure extreme value conditions of blowout;

scene 2, air pressure balance inside the shaft: the manhole cover is provided with vent holes to communicate the underground pipeline with the ground atmosphere, so that the non-constant air pressure in the vertical shaft and the underground pipeline is supplemented and balanced in time, a driving pressure difference extreme value of a blowout phenomenon is formed in a flattening mode, and the condition of blowout occurrence is further inhibited;

scene 3, when the blowout phenomenon still occurs inevitably, the well cover starts a water-gas separation function to deal with the blowout with different strengths, and when the height of the blowout is lower than that of the well cover, the scene 2 is obtained; when the height of the well blowout is in contact with the height of the well lid and the impact force is not enough to balance the weight of the well lid, the sprayed water-vapor mixture collides with the wall surface of the step or the well lid, part of the water-vapor mixture falls back to the underground pipeline, and the other part of the water-vapor mixture overflows or falls back to the underground pipeline after being separated through the vent holes of the well lid; if the blowout strength is greater than the preset value, even when the well cover or the middle hole top cover is pushed open, the middle hole emergency device or the limiting device is started, unstable air pressure is released quickly, and blowout is avoided.

8. The blowout abatement method of an inverted stepped shaft structure according to claim 7, wherein: scene 1 and scene 2 are mutually responsive, the condition for forming the blowout is inhibited to the greatest extent, when the blowout still occurs, the condition is scene 3, and at the moment, scene 1 and scene 2 still play a role, so that the blowout is reduced and avoided together.

9. The blowout abatement method of an inverted stepped shaft structure according to claim 7, wherein: multistage inverted steps in scenario 1 can intercept the airbag to be released, the airbag is shifted, the position of the airbag is shifted, and the airbag is staggered from a shaft well mouth, so that the airbag cannot be directly sprayed out of the shaft well mouth when the splashing phenomenon occurs, meanwhile, the enlargement of the bottom space of the shaft means the length of an open flow section is increased, the transition conversion between pressure flow and non-pressure flow is facilitated, and the centralized occurrence of multiple complex flow states at the outlet position of the traditional shaft is avoided.

Technical Field

The invention belongs to the technical field of municipal engineering and hydraulic engineering, and particularly relates to an inverted step type vertical shaft structure and a blowout reduction and avoidance method thereof.

Background

In municipal works, underground pipe networks are criss-cross and comprise sewage discharge pipe networks, cable pipe networks, water supply pipe networks and the like, the street ground is often provided with well covers for plugging the inlets of the pipe networks, and the structure for communicating the ground with the underground pipe networks is often called a vertical shaft and generally has the functions of water collection, ventilation, people communication and the like. Typically, these shafts are designed as a vertical shaft-like conduit with vertical walls, the upper part of which is closed with a well cover.

In recent years, the drainage load of municipal drainage networks has increased as the underlying surface of the city has solidified. Generally speaking, the water flow state of a municipal drainage pipe network system is designed to be non-pressure flow with a free water surface, when short-term heavy rainfall is experienced, the flow of a drainage pipe network is increased sharply, when the short-term heavy rainfall exceeds the drainage capacity of a pipeline, the water flow state is transited to full flow from open channel flow, a large-volume intercepting air bag is possibly formed at the position of the slope change and the confluence of branch pipes, air is transferred to a vertical shaft after continuous compression, and the air rises along the vertical shaft to form a water column or water-air mixed jet flow so as to form a blowout phenomenon. The blowout can not only generate larger instantaneous pressure to induce the problems of pipeline vibration and even structural failure, but also lift the well cover of the vertical shaft to damage the safety of pedestrians and vehicles; for rain and sewage combined drainage pipelines, local flood caused by blowout causes problems of environmental pollution and the like. Particularly, in recent years, the extremely severe weather is frequent, the short-time heavy rainfall disaster of cities is easily formed, and the frequency of the well blowout accidents of the drainage vertical shafts of the urban sewer pipelines is also increased. Therefore, measures are required to reduce or avoid the occurrence of blowout phenomenon and ensure public safety.

At present, related researches on urban pipe network vertical shaft blowout at home and abroad are few, and the generation conditions and the reduction and avoidance measures are insufficient. Summarizing, the current proposed abatement measures are mainly the following: (1) the pipe diameter of the vertical shaft is increased, and researches show that the instantaneous extreme pressure can be reduced when blowout occurs by increasing the pipe diameter of the vertical shaft (to the same size as the main pipeline), however, the method can not avoid the possibility of blowout occurrence, and the pipe diameter of the vertical shaft cannot be increased without limit in practical application; (2) the method is characterized in that a well cover with small holes is arranged at the top of a vertical shaft, the principle of the method is that the extreme value of water flow pressure is reduced, the flux of the vertical shaft is restrained, and therefore the spraying of a water-vapor mixture is restrained, however, the method often hinders the outflow of gas when the blowout strength is high, the change of the air pressure in a pipeline is increased, and the possibility of blowout occurrence cannot be avoided; (3) a buffering structure, such as an elastic supporting rubber ball or a baffle plate, is arranged below the well cover, and the principle of the buffering structure is that energy dissipation and water-gas separation are carried out on the water jet flow, but trouble is brought to the maintenance of the vertical shaft.

Therefore, how to improve the flow state of water flow at the position of the vertical shaft from the source and avoid the blowout phenomenon becomes the key of research in the field.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide an inverted step type vertical shaft structure and further provides a blowout reduction and avoidance method based on the structure so as to solve the problems in the prior art.

The technical scheme is as follows: the utility model provides a reverse step formula shaft structure, is including setting up in the shaft cavity at underground piping top, set up in the well lid at shaft top, and set up the multistage wall of falling the step of shaft both sides.

In a further embodiment, the inverted step wall is a mirror image along the opening axis of the shaft, and the step width is greater than the underground pipe width.

In a further embodiment, a first step in the multi-stage inverted steps is flush with the ground, and a cylinder is dug out from the center to form a vertical shaft mouth; the last step is connected with the top of the underground pipeline, and the gradient of the middle step is 30-60 degrees; and the backfill above the step is flush with the ground.

In a further embodiment, the well lid is provided with vent holes and vent middle holes, and the vent holes are communicated with the underground pipeline and the ground atmosphere; the vent holes are distributed in an array mode, and the aperture is 2 cm-5 cm; the ventilation center hole is located at the center of the well cover, the aperture of the ventilation center hole is larger than that of the ventilation hole and ranges from 10cm to 30cm, the ventilation center hole is provided with a top cover, one end of the top cover is hinged, and the other end of the top cover is clamped into the clamping groove.

In a further embodiment, the well lid is fixed on the shaft base through a well lid support, the well lid hinge is fixed on the well lid, and the well lid hinge is installed on the well lid support; the upper side of the well lid is provided with a lifting handle.

In a further embodiment, the well lid is an inverted conical table, the well lid is horizontally placed when the well lid is used, the top surface of the well lid is flush with the ground, the section of the well lid is an inverted isosceles triangle, and the base angle of the triangle is 30-50 degrees; a plurality of vent holes with the same specification are formed in the side face of the well lid cavity, the opening axis direction of each vent hole is perpendicular to the wall face, and the vent holes are communicated with the well lid cavity and the inside of the vertical shaft; and the vertex of the cone of the cavity of the well lid is vertically provided with a hole.

In a further embodiment, the total area of the side vent holes of the well lid cavity is slightly larger than the total area of the open air holes of the ground flat plate.

In a further embodiment, the well lid is fixed in ground through the well lid support, and on the well lid hinge was fixed in the well lid support, the well lid outer fringe set up the well lid floor, and the well lid floor set up "S" type floor track, the well lid hinge slides in "S" type track.

A method for releasing an entrapped air bag of a reverse step type vertical shaft structure comprises the following three scenes and the corresponding steps:

scenario 1: multi-stage gas pressure release: the underground pipeline water flow is connected with a vertical shaft in a transition mode through a multi-stage inverted step body type with a suddenly expanded top, the inverted step body type structure is beneficial to gas overflow and gas bag release in the pipeline, gas is not easily involved in reverse flow, and the existing trapped gas bag at the top of a main flow is stably released from the mechanism and is restrained from forming a new large gas bag, so that the multi-stage inverted step body type achieves the effect of multi-stage release of non-constant gas pressure, and meanwhile, pressure extreme values which are continuous in time and concentrated in space are dispersed into discontinuous pressure extreme values which are multipoint in space, and the extreme pressure condition of blowout occurrence is restrained;

scenario 2: and (3) balancing the air pressure in the vertical shaft: the manhole cover is provided with vent holes to communicate the underground pipeline with the ground atmosphere, so that the non-constant air pressure in the vertical shaft and the underground pipeline is supplemented and balanced in time, a driving pressure difference extreme value of a blowout phenomenon is formed in a flattening mode, and the condition of blowout occurrence is further inhibited;

scenario 3: when the well blowout phenomenon is unavoidable, starting a water-gas separation function of the well cover to deal with the well blowout with different strengths, wherein when the height of the well blowout is lower than that of the well cover, the situation is 2; when the height of the well blowout is in contact with the height of the well lid and the impact force is not enough to balance the weight of the well lid, the sprayed water-vapor mixture collides with the wall surface of the step or the well lid, part of the water-vapor mixture falls back to the underground pipeline, and the other part of the water-vapor mixture overflows or falls back to the underground pipeline after being separated through the vent holes of the well lid; if the blowout strength is greater than the preset value, even when the well cover or the middle hole top cover is pushed open, the middle hole emergency device or the limiting device is started, unstable air pressure is released quickly, and blowout is avoided.

Has the advantages that:

1. the underground pipeline water flow is connected with the vertical shaft in a transition mode through the multi-stage inverted step body type, so that gas in the pipeline is favorably overflowed and released by the air bag, the gas is not easily involved in the reverse flowing direction, the formation of the air bag is intercepted in a large scale from the mechanism, the non-constant gas pressure can be released in a multi-stage mode, the pressure extreme value which is continuous in time and concentrated in space is dispersed into the pressure extreme value which is discontinuous in multiple points in space, and the formation of well blowout occurrence conditions is restrained.

2. The trapped air bag is released, the position is shifted, the well mouth of the vertical shaft is staggered, the trapped air bag cannot be directly sprayed out of the well mouth of the vertical shaft even if splashing occurs, meanwhile, the enlargement of the bottom space of the vertical shaft means that the length of the open flow section is increased, the conversion between the flow state with pressure flow and the flow state without pressure flow is facilitated, and the multiple complex flow state at the outlet position of the vertical shaft is avoided.

3. The well lid is provided with the vent holes to communicate the underground pipeline and the ground atmosphere, so that the non-constant air pressure in the vertical well and the underground pipeline is balanced, the air pressure in the pipeline is balanced in advance, the driving pressure difference extreme value of the well blowout phenomenon is formed by the well lid in a flattening manner, and the formation of the well blowout occurrence condition is inhibited. The existing urban drainage pipe shaft well cover is directly sealed by a solid well cover, most well covers are independent bodies (unfixed), air pressure in the shaft and an underground pipeline is unstable, fluctuation is large, the possibility of well blowout is large, and the well cover is easy to fly up when well blowout strength is large.

4. The shaft structure is combined with the well cover with the vent hole, and the multistage measures are adopted to ensure that the air pressure in the shaft is stable, so that the occurrence of blowout of the shaft is reduced and avoided.

Drawings

Fig. 1 is a sectional view of an inverted stepped shaft structure.

Fig. 2 is a top view of the inverted stepped shaft structure.

Fig. 3 is a sectional view of the inverted stepped shaft well cover.

Fig. 4 is a top view of the inverted stepped shaft well lid.

Fig. 5 is a cross-sectional view of a schematic view of a structure and installation method of the manhole cover assembly.

Fig. 6 is a detailed view of the structure and working principle of the manhole cover assembly.

The figures are numbered: underground pipeline 1, ground 2, shaft 3, backfill 4, well lid 5, well lid ribbed slab 501, ribbed slab track 502, limiting soft rope 503, well lid cavity 504, well lid support 505, well lid hinge 506, soft rope support 507, soft cushion 508, intercepting air bag 6, shaft base 7, shaft step 8, vent hole 10, vent hole 11, hole lid 12, shaft hinge 13, hinge base 14, lifting handle 15.

Detailed Description

The applicant believes that the 3-well blowout relief measures of the urban pipe network vertical shaft which are common at present have the following three modes:

1. the diameter of the vertical shaft is increased to reduce the instantaneous extreme pressure when the blowout occurs, however, the diameter of the vertical shaft cannot be increased without limit in practical application by the method, the method has limitation in practical application, and the possibility of the blowout cannot be avoided;

2. set up buffer structure below the well lid, like elastic support's rubber ball or baffling board etc. its principle lies in energy dissipation and aqueous vapor separation to the injection rivers, but the effect is relatively poor when meetting strong transient flow change, has hindered gaseous discharge even, worsens the trunk line flow state, also can bring the trouble for the shaft overhauls simultaneously.

3. The method is characterized in that a hole and a limiting well cover are arranged at the top of a vertical shaft, the principle of the method lies in that the extreme value of water flow pressure is reduced, and water-vapor mixture is separated in multiple stages.

Therefore, the invention aims to improve the flow state of water flow at the interface of the vertical shaft 3 and the underground pipeline 1 from the source, inhibit the well blowout occurrence condition and avoid the well blowout phenomenon by designing the inverted step type vertical shaft structure.