Internal support of foundation pit demolition blasting vibration safety monitoring system and monitoring method
Technical field:
The present invention relates to a kind of basis, underground structure, more specifically to a kind of internal support of foundation pit demolition blasting vibration safety monitoring system and monitoring method.
Background technology:
Needing to set up temporary support in foundation pit construction, temporary support structure is determined according to foundation pit structure. Foundation ditch builds up rear temporary support to be needed to remove, and conventional dismounting means have demolition blasting, mechanical removal, manual demolition, lifting to remove. Demolition blasting has the advantages that the duration is short, effective, cost is low, is widely used. Further, along with the development of city foundation ditch technology, Large Foundation Pit continues to bring out, and temporary support structure together, more complicated, huge with it, and demolition blasting becomes the important means that temporary support is removed.
At present, method for monitoring safety status of foundation pit is primarily directed to foundation ditch monitoring of various item securities in construction, and monitoring object includes: the sedimentation of underground utilities, underground installation, surface road and building, displacement;The sedimentation on maintaining pile top and horizontal displacement; Fender post, horizontal support STRESS VARIATION; Soil body lateral displacement outside foundation ditch; Cheat the delaminating deposition of outer sub-surface; The water table measure that foundation ditch is inside and outside; Soil pressure in the soil body of underground and pore water pressure; End resilience monitoring in hole in foundation ditch. It is CN101644065A that Chinese invention patent publication discloses Authorization Notice No. on February 10th, 2010, the patent No. is 200910194521.4, patent name is the patent of invention of " a kind of method for monitoring safety status of foundation pit ", which propose to make up and current pit retaining monitoring and safety evaluation lack the deficiency processing rational judgment deep pit monitor state according to data, but when being not directed to foundation ditch blasting demolition girder, the safety monitoring of foundation pit structure is studied.
The safety utilizing vibration deformation monitoring building in recent years has been reported, but not yet with good grounds foundation ditch self vibration characteristic judges the research of foundation pit structure damage effect during blasting demolition girder, present invention research it is important that the fast and convenient judgement each blasting demolition girder degree of impairment to foundation ditch body construction.
Summary of the invention:
It is an object of the invention to provide a kind of for prior art weak point and can quickly judge the foundation ditch blasting demolition girder internal support of foundation pit demolition blasting vibration safety monitoring system to foundation ditch body construction damage effect.
It is a further object to provide the monitoring method of a kind of above-mentioned vibration safety monitoring system.
It is an object of the invention to be realized by following measures: a kind of internal support of foundation pit demolition blasting vibration safety monitoring system, it is characterized in that, include by some being arranged in the vibrating sensor of the some measuring points of internal support of foundation pit, data line, data collecting instrument, data/address bus, computer processing system are formed, the vibrating sensor of described each measuring point is connected by data line and data collecting instrument, and data collecting instrument is connected by data/address bus and computer processing system.
The vibrating sensor of described measuring point is single channel vibrating sensor, arranges a vibrating sensor by one-dimensional direction, described one-dimensional direction be in horizontal plane with measuring point and quick-fried source line in the same direction.
The vibrating sensor of described measuring point is single channel vibrating sensor, two vibrating sensors are arranged by two-dimensional directional, a direction in described two-dimensional directional be in horizontal plane with measuring point and quick-fried source line in the same direction, second direction is tangent with measuring point and line direction, quick-fried source in horizontal plane.
The vibrating sensor of described measuring point is single channel vibrating sensor, three vibrating sensors are arranged by three-dimensional, a direction in described three-dimensional be in horizontal plane with measuring point and quick-fried source line in the same direction, second direction is tangent with measuring point and line direction, quick-fried source in horizontal plane, and the 3rd direction is the direction being perpendicular to described horizontal plane straight up.
To achieve these goals, the technical scheme that the monitoring method of the present invention adopts comprises the concrete steps that:
The first step, determines foundation ditch internal vibration point position according to beam explosive scheme, chooses according to foundation pit structure and is damaged, by blasting vibration, the monitoring point that probability is maximum;
Second step, installs vibrating sensor at vibration measuring point, or three-dimensional one-dimensional or two-dimentional by designing requirement is layouted, and monitoring obtains the monitor value of each monitoring point during foundation ditch beam explosive;
3rd step, adopts spectrum analysis and frequency splitting technology to process Monitoring Data, extracts the vibration extreme value under characteristic frequency, and the vibration ratio of extreme values that the monitor value of each monitoring point and foundation ditch can be born relatively, determines the safe condition of foundation ditch according to fiducial value.
In the described first step, described beam explosive scheme adopts foundation ditch to support subregion or layering explosion.
In the described first step, the quantity of described foundation ditch internal vibration measuring point is no less than 5.
In the described first step, described foundation ditch internal vibration point position is the layer outside explosion supports place layer, all arranges vibration monitoring point at the diaphram wall of foundation ditch every layer supporting plane, supporting construction type place.
In the described first step, described foundation ditch internal vibration point position makes foundation ditch each layer measuring point have maximum coincidence on horizontal plane.
In described second step, described layout as with measuring point and quick-fried source line for reference by three-dimensional, be respectively arranged into reference direction in the same direction, tangent and vertical direction.
In described 3rd step, the data extreme value that described deep pit monitor state is after being processed all monitoring points vibrates ratio of extreme values relatively with deep pit monitor, if all monitoring points fiducial value is respectively less than 1, illustrates that foundation ditch will not be produced damage by beam explosive; If some fiducial value is more than 1, illustrate that the monitoring point place that these fiducial values are corresponding is likely to be supported blasting vibration damage.
Compared with prior art, owing to have employed internal support of foundation pit blasting vibration security archiecture and the monitoring method that the present invention proposes, the beam explosive degree of impairment to foundation pit structure can be judged according to the vibration of monitoring point in foundation ditch, compare with the monitoring method of tradition fault localization, can the fast and convenient judgement each beam explosive degree of impairment to foundation ditch body construction, thus evaluating each demolition effect, revising blasting parameter, reducing the beam explosive damage to foundation ditch. This method have quick, easy, cost is low, the feature of good environmental adaptability, is suitable for the monitoring of the deep pit monitor of various internal support of foundation pit explosion, to foundation ditch beam explosive safe construction control significant.
Accompanying drawing illustrates:
Fig. 1 is foundation ditch internal vibration safety monitoring system figure.
Fig. 2 is the schematic diagram of Blast Vibration Monitoring in a foundation ditch.
Fig. 3 is the monitoring point A vibration monitored vibration primary signal.
Fig. 4 is that the vibration vibration primary signal to monitoring point A carries out the amplitude spectrum curve that FFT process obtains.
Fig. 5 is to the monitoring point A vibration vibration filtered signal of primary signal.
Detailed description of the invention:
Below in conjunction with accompanying drawing, detailed description of the invention is elaborated:
Fig. 1 is foundation ditch internal vibration safety monitoring system figure. In figure, a kind of internal support of foundation pit demolition blasting vibration safety monitoring system, include by some being arranged in the vibrating sensor 1 of the some measuring points of internal support of foundation pit, data line 2, data collecting instrument 3, data/address bus 4, computer processing system 5 are formed, described each vibrating sensor 1 is connected by data line 2 and data collecting instrument 3, and data collecting instrument 3 is connected by data/address bus 4 and computer processing system 5. In native system, vibrating sensor 1 and data collecting instrument 3 are for collection in worksite vibration data, and computer processing system 5 is used for carrying out later data process. The vibrating sensor and the data collecting instrument that use in the present embodiment are the TC-3850 vialog of city's confession and supporting sensor. The layout of measuring point is one-dimensional or two-dimentional by designing requirement or three-dimensional is layouted, and monitoring obtains the monitor value of each monitoring point during foundation ditch beam explosive. Described one-dimensional direction X be in horizontal plane with measuring point and quick-fried source line in the same direction; A direction X in described two-dimensional directional be in horizontal plane with measuring point and quick-fried source line in the same direction, second direction Y is tangent with measuring point and line direction, quick-fried source in horizontal plane; A direction X in described three-dimensional be in horizontal plane with measuring point and quick-fried source line in the same direction, second direction Y is tangent with measuring point and line direction, quick-fried source in horizontal plane, 3rd direction Z is the direction being perpendicular to described horizontal plane straight up, X, Y, Z tri-direction meet the right-hand rule.In general, measuring point records the vibration velocity in three directions constituting rhombic system, it is determined that the sum velocity of this measuring point is comparatively accurate, certainly also will be according to actual needs. Some sensor of existing market can record the vibration velocity in three directions simultaneously, therefore the type sensor only needs one namely can determine that single measuring point three direction speed. The present embodiment is in actual test process, and the vialog TC-3850 of employing has multiple passage, and the corresponding sensor of each passage, each sensor is only capable of gathering the vibration signal in a direction. Therefore measuring point needs two horizontal VHR��VHTWith one vertically to VZVibrating sensor. Described VHRI.e. X-direction, VHTI.e. Y-direction, VZI.e. Z-direction. Three directions meet the right-hand rule and arrange. Owing to three-dimensional vibration data can describe the situation of measuring point more accurately, therefore should ensure that many monitoring points have three-dimensional vibration data as far as possible.
The monitoring method of this device is made up of the following step:
The first step, determines foundation ditch internal vibration point position according to beam explosive scheme, chooses according to foundation pit structure and is damaged, by blasting vibration, the monitoring point that probability is maximum. During internal support of foundation pit demolition blasting, the vibration that explosion produces is transmitted to foundation ditch by structure, makes foundation ditch body construction produce judder, and foundation pit structure is disadvantageous by this vibration, for weakening the consequence that vibration brings, internal support of foundation pit explosion often adopts subregion or layering explosion. The quantity of usual foundation ditch internal vibration measuring point is no less than 5. Foundation ditch internal vibration point position is the layer outside explosion supports place layer, and the diaphram wall of foundation ditch every layer supporting plane of being everlasting, supporting construction type place all arrange vibration monitoring point. Described foundation ditch internal vibration point position should make foundation ditch each layer measuring point have maximum coincidence on horizontal plane, so increases the comparability of data.
Second step, installs vibrating sensor at vibration measuring point, or three-dimensional one-dimensional or two-dimentional by designing requirement is layouted, and monitoring obtains the monitor value of each monitoring point during foundation ditch beam explosive. Fig. 2 is the schematic diagram of Blast Vibration Monitoring in a foundation ditch. In figure, shadow region be in this layer support lower section treat quick-fried supporting zone, it is assumed that be respectively arranged tetra-vibration velocity monitoring points of A, B, C, D at this layer. Wherein, measuring point A is positioned on supporting plane, and B, C, D are arranged in foundation ditch diaphram wall. Monitoring point A monitors the vibration of this measuring point vertical direction.
3rd step, adopts spectrum analysis and frequency splitting technology to process Monitoring Data, extracts the vibration extreme value under characteristic frequency, and the vibration ratio of extreme values that this value and foundation ditch can be born relatively, determines the safe condition of foundation ditch according to fiducial value. When processing monitoring point Monitoring Data in foundation ditch, spectrum analysis and frequency splitting processing technique should be adopted, concrete grammar is as follows: first vibration velocity curve is carried out fft analysis, process obtains amplitude spectrum curve, peak value is searched out on the occasion of segment at amplitude spectrum curve, take 30%��50% peak value as basis reference, be the frequency separation that filtering should take more than the frequency band corresponding to the crest of basis reference. Original vibration velocity signal carries out interval filtering, and the vibration velocity peak value that filtering obtains is the vibration velocity extreme value of this measuring point. The data extreme value that described deep pit monitor state is after being processed all monitoring points vibrates ratio of extreme values relatively with deep pit monitor, if all monitoring points fiducial value is respectively less than 1, illustrates that foundation ditch will not be produced damage by beam explosive; If some fiducial value is more than 1, illustrate that the monitoring point place that these fiducial values are corresponding is likely to be supported blasting vibration damage.Fig. 3 is the measuring point A vibration velocity primary signal monitored, and first needs this original vibration velocity signal is carried out FFT process, i.e. fast Fourier transform, obtains the amplitude spectrum curve shown in Fig. 4. To amplitude spectrum tracing analysis, it is known that: amplitude spectrum peak of curve is 0.246, takes peak value 50% as basis reference (namely 0.126), makes reference reference horizontal line, see Fig. 4. Find frequency separation section: the crest in crest P2/P3 respective frequencies interval is all above basis reference horizontal line, and the crest being positioned at outside P2/P3 respective frequencies segment is positioned at below reference horizontal line. Therefore the frequency filtering that frequency separation section 12��110Hz is the filtering of measuring point A interval that P2/P3 is corresponding. Next the primary signal in Fig. 2 is carried out the filtering of 12��110Hz interval, obtains filtered vibration velocity signal shown in Fig. 5. Fig. 5 is analyzed known: filtered vibration velocity peak value VA(max)For 6.47cm/s. If the marginal vibration speed V that this foundation ditch allowsSFor 8cm/s, then this measuring point vibration velocity safety value ��A=6.47/8=0.81 < 1. Accordingly it can be seen that this monitoring point is safe when beam explosive.
The vibration velocity signal according to said method successively B, C, D monitoring point surveyed is analyzed. If B, C, D vibration signal final peak value respectively VB(max)=7.50cm/s, VB(max)=9.27cm/s, VB(max)=12.90cm/s. Then the vibration velocity safety value of these three measuring point is respectively as follows:
��B=7.50/8=0.94 < 1; ��C=9.27/8=1.16 > 1; ��D=12.90/8=1.61 > 1.
Known accordingly: during foundation ditch beam explosive, B place, monitoring point foundation pit structure is safe, and C, D place, monitoring point foundation pit structure can be subject to certain damage. Monitoring result illustrates that this beam explosive scheme blasting parameter design is unreasonable, need to improve, and needs C, D place, monitoring point structure carries out flaw detection research simultaneously.
The present invention judges the beam explosive degree of impairment to foundation pit structure according to the vibration velocity of monitoring point in foundation ditch. With tradition fault localization monitoring method compare, this method have quick, easy, cost is low, the feature of good environmental adaptability, is suitable for the monitoring of the deep pit monitor of various internal support of foundation pit explosion, to foundation ditch beam explosive safe construction control significant.
Above-described embodiment is not intended that limitation of the present invention, as long as the technical scheme adopting the form of equivalent replacement or equivalent transformation to obtain, all falls within protection scope of the present invention.