CN1928260A - Method for foundation pile end hole rock character detection and judgment technique - Google Patents
Method for foundation pile end hole rock character detection and judgment technique Download PDFInfo
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- CN1928260A CN1928260A CN 200510037064 CN200510037064A CN1928260A CN 1928260 A CN1928260 A CN 1928260A CN 200510037064 CN200510037064 CN 200510037064 CN 200510037064 A CN200510037064 A CN 200510037064A CN 1928260 A CN1928260 A CN 1928260A
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Abstract
The invention relates to a measuring and deciding technology for aperture lithologic characters of the pile bottom, characterized in that the intensity and constitution of underground rock stratum are analyzed through measuring shake frequency of oscillatory wave generated by heavy bob attacking rock stratum under hole by measuring machine for aperture lithologic characters of the pile bottom so as to appreciate characters of underground rock stratum in quantity. Combined with geologic drilling report and ballast height mark of pile bottom hole is decided exactly so as to assure the load of pile foundation, rational saving and avoid project quality accident. The technology with simple operation can be mastered by those skilled.
Description
Whole hole technology at the bottom of the stake of pore-creating filling pile is on the spot in the past normally comprehensively judged according to geological drilling report, pore-forming rock quarrel, pore-forming rate of penetration.But it is very complicated that geology changes, especially locate at stratum breaking band, limestone geology and geomorphology etc., geology with Φ 60, Φ 101 is bored the actual conditions that core is difficult to accurately estimate the stratum, the result who often appears at two or three the brill cores in the same stake position is inconsistent, underground critical terrain feature, also usually fail to disclose as weak intercalated layer, solution cavity etc., in addition in order to save the geological drilling expense, the density of geological drilling can not satisfy actual requirement usually, also has shoddy geological drilling report socially really.According to designing absolute altitude whole hole in whole hole at the bottom of the bearing pile of foundation geological drilling report design, the socketed pile stake, great economic loss or serious hidden dangers in project usually appear.The drilling construction process is according to pore-forming rock quarrel and pore-forming rate of penetration, come whole hole absolute altitude at the bottom of the synthetic determination stake in conjunction with geological drilling report, because the rock quarrel is the core of rock, the rock quarrel state of same place Different Strata is approximate or similar, and veteran geomatics engineer also is difficult to accurate evaluation.The pore-forming rate of penetration is removed outside the Pass intensity with the rock stratum has, and is also relevant with factors such as toughness, hammehead structure and the impact energy of rock, mud property, deslagging methods.Although therefore adopt the control measures in design liaison, representative of Party A, management, whole hole, unit in charge of construction four directions, the whole hole result in the stake end of mistake also often occurs.Data according to palm certificate, the province every year that has because of stake at the bottom of the whole hole of the mistake direct losses that cause of doing over again reach tens million of units, and these generally mostly occur and loose core on the important foundation of check pile bottom force holding layer must carrying out pile foundation, and the workmanship hidden danger that exists for common engineering more is difficult to estimate.
Because the whole hole of existing pile foundation technology is relatively backward, judge and blur, have many uncertain factors, and quality accident and hidden danger of quality often occur, exert heavy pressures on to the engineer, so more be to lose and the wasting of resources on the other hand on pile foundation engineering because of the excessively conservative national wealth that causes.If have 5000 piles, wherein the average every pile stake of 3000 piles is long increases by 2 meters than actual needs, will increase about direct input more than 1,500 ten thousand yuan such as an expressway construction engineering; Also to go into rock drilling construction difficulty big because of pile foundation, also consumed the profit of about ten thousand yuan of the construction about 1000-2000 of contractor unit simultaneously.As seen causing the national wealth and the wasting of resources to decuple the loss that error in judgement causes because of excessively conservative, is more massive loss! In today of China's infrastructure development in an all-round way, annual because of the whole hole direct losses that cause backward in technique of pile foundation and wasting of resources accumulative total far away from more than 1,000,000,000 yuan.
Existing engineering geophysics technology, as electric exploring method, seismic refraction method, geological radar and acoustic logging etc., apparatus expensive, operation and analytical technology complexity, degree of specialization requires high, judged result exists multi-solution and ambiguity, using all has certain limitation, can't slap certificate and use for numerous engineers and technicians.For guaranteeing workmanship, to go through on pile foundation construction quality control and the hypervisor: design geology pre-test, design geology be detailed to be visited, construction geology is mended and visited, cubic whole hole and pile quality detect (as small strain detect, quiet stake test, drilled drawing-core) five stages, this wherein needs many fund inputs and time loss.
The purpose of this invention is to provide a kind of new easy, reliable physical prospecting technology, send features such as vibration wave frequency by tension weight churning rock stratum in the measurement pile foundation pore forming process, analyze the intensity and the structure of subterranean strata, reach the purpose that digitlization qualitatively judges the characteristic of subterranean strata, accurately judge the stake end whole hole absolute altitude in conjunction with geological drilling report, rock quarrel quarrel sample etc., thereby reach the effect of guaranteeing bearing capacity of pile foundation, rationally saving, avoid accident resulting from poor quality of projects and hidden danger of quality.
The method of foundation pile end hole rock character detection and judgment technique of the present invention, it is characterized in that detection of dynamic instrument (1) is placed to sensor (3) by lead (2) in the mud (5) of pore-forming (4) of pile foundation, the excited frequency fa of the shock oscillation ripple that sends in the time of on the scar of the rock stratum (7) at the bottom of detection weight (6) impact opening, or exciting umber of pulse Na, according to the elastic collision theory, by analyzing the excited frequency fa of shock oscillation ripple, or the dependency relation of the compressive strength of rock R of exciting umber of pulse Na and rock stratum (7), thereby calculate the compressive strength of rock R of tested rock stratum (7), as the main foundation of the whole hole of pile foundation absolute altitude judgement.
According to the elastic collision theory, the excited frequency fa of the shock oscillation ripple that weight (6) and rock stratum (7) collision are sent, main relevant, also relevant with bell weight, bell matter, fall distance, contact area, collision course and impact velocity with rigidity, hardness (intensity), the modulus of elasticity of rock stratum.The intensity of two articles is the high more fa of excited frequency of HI high impact generation more; Excited frequency fa is also relevant with the architectural feature factor that constitutes rock stratum rigidity, as thickness, structure, substratum condition etc.In pile foundation drilling construction and testing process, weight (6) is relatively as a standard body, bell weight, bell matter, the relative unanimity of fall distance, contact area, collision course and impact velocity, so the variation of excited frequency fa mainly reflects the intensity of tested rock stratum and the otherness of strata structure feature.When the rock stratum is enough thick, can be considered a rigid body, the excited frequency fa that bump sends in the shock wave is main relevant with the compressive strength of rock R of rock stratum, therefore can set up the dependency relation of the compressive strength of rock R of excited frequency fa and rock stratum (7), the main foundation of utilizing this relation to judge as the whole hole of pile foundation (4) absolute altitude.When rock stratum (7) reduced thickness, lithology weathering, fragmentation or when having weak intercalated layer, cave etc., the integral rigidity of rock stratum (7) reduces, the excited frequency fa that collision produces also decreases, this with because the compressive strength of rock R of rock stratum (7) reduces equally, reflect that ground can hold the bearing capacity of confession and also decrease.Rock stratum (7) the lithology uniformity that is impacted, the waveform of the shock oscillation ripple that every hammer produces is same or similar, and the deviation value of excited frequency fa is little; The lithology lack of homogeneity of rock stratum if (7), rock matter, crack change greatly, and the wave form varies of shock oscillation ripple is big, poor repeatability, and the deviation value of excited frequency fa also increases.Therefore by detecting the statistical analysis and the processing of data, can judge the state and the variation tendency of tested rock stratum.
The special-purpose detection of dynamic instrument (1) that a kind of foundation pile end hole rock character detector of the present invention (8) detect to be judged as foundation pile end hole rock character, it is held to levy and is that foundation pile end hole rock character detector (8) is made up of amplifying circuit (8-1), shaping circuit (8-2), trigger (8-3), time base circuit (8-4), frequency divider (8-5), gating circuit (8-6), gate circuit (8-7), counter (8-8), display (8-9) etc.Analog electrical signal by the detected shock oscillation ripple of sensor (3) amplifies through amplifying circuit (8-1), and be treated to data signal through shaping circuit (8-2), simultaneously the shock oscillation ripple through trigger (8-3) from pulse signal of triggering for generating, pulse signal starts the reset terminal of frequency divider (8-5) and the set end of gating circuit (8-6) simultaneously, the input of frequency divider (8-5) is connected to the output of time base circuit (8-4), hold for the standard time-base signal by time base circuit (8-4), frequency divider (8-5) resets gating circuit (8-6) to setting signal of time-delay back generation, the switch time of gating circuit (8-6) regulating gate circuit (8-7), the exciting umber of pulse of shock oscillation ripple is counted by counter (8-8) under the control of gate circuit (8-7), thereby detect the exciting umber of pulse Na of shock oscillation ripple, and the excited frequency fa that converts.
Of the present invention hold to levy be the shock oscillation ripple is divided into main reflection rock stratum (7) percussion excitation phase and two periods of structure forced vibration stage on time-histories, measure and analyze excited frequency fa and exciting umber of pulse Na and the vibratory impulse in vibration frequency fb or above-mentioned two periods of two periods respectively and count Nb, variation and relation that excited frequency fa by analyzing two periods and vibration frequency fb or exciting umber of pulse Na and vibratory impulse are counted Nb are calculated the compressive strength of rock R of rock stratum (7) and are analyzed the otherness of rock stratum (7) structural feature.The shock oscillation ripple is divided into main reflection rock stratum (7) percussion excitation phase and two periods of structure forced vibration stage are detected respectively on time-histories, by refinement instrument detecting method, improved the detection accuracy of excited frequency fa and vibration frequency fb, release is to detecting the last handling process of data complexity, make the check and analysis process direct and easy, be fit to numerous engineers and technicians and use, the technology that helps is promoted.
It holds a kind of foundation pile end hole rock character detector of the present invention (8) to levy and is that foundation pile end hole rock character detector (8) has increased wave filter (8-10), shaping circuit II (8-11), gating circuit II (8-12), gate circuit II (8-13), counter II (8-14), display circuit II (8-15).The input of wave filter (8-10) and output are connected respectively to the output of amplifying circuit (8-1) and the input of shaping circuit II (8-11), by the accumulation signal of wave filter filtering high frequency.Set end, reset terminal, the output of gating circuit II (8-12) is connected respectively to output, another output of frequency divider (8-5), gate circuit II (8-13) control end of gating circuit (8-6), makes gating circuit produce opening the door the control time corresponding to rock stratum (7) the main stage of shaking of forced vibration.The input of gate circuit II (8-13) and output are connected respectively to the input of the output sum counter II (8-14) of shaping circuit II (8-11), show the shake vibratory impulse number on rank of the master of rock stratum (7) forced vibration by display II (8-15) at last.
Of the present invention hold to levy be that detection of dynamic instrument (1) detects the waveform of storage shock oscillation ripple by A/D converter (9) and computer or microcomputer (10), utilize excited frequency fa, the vibration frequency fb etc. of analysis shock oscillation ripples such as FFT technology, judge the tx time of advent of back wave by the amplitude of vibrational waveform, the equal feature of shaking, according to the propagation law of elastic wave, structural feature and othernesses such as the compressive strength of rock R of the tested rock stratum of analysis-by-synthesis (7), lift height hx.The shock oscillation ripple comprises the back wave composition that shock wave is propagated in the rock stratum, can utilize the propagation law of elastic wave to calculate the position in thickness, weak intercalated layer or the cave of rock stratum.When the rock stratum was deck, the waveform of shock oscillation ripple was more clear, better regularity; If tested crushing rock formation or interlayer are many, then vibrational waveform disorder, poor repeatability, amplitude fading are fast.
Of the present invention hold to levy be simultaneously by absolute altitude at the bottom of deep hole measuring equipment (11) measured hole, in foundation pile end hole rock character detector (8), increase counter III (8-16) and display III (8-17), and the output that is connected to gating circuit (8-6) is used to write down hammering and counts M.By analyzing mean oscillatory frequency f a, fb or mean oscillatory umber of pulse Na, the Nb that pore-forming passes through each rock stratum (7), indexs such as M, pore-forming rate of penetration Vh are counted in the accumulative total hammering, and compressive strength of rock R of each rock stratum of analysis-by-synthesis (7) and structure are held the otherness of levying.Hole depth measuring equipment (11) by forward-backward counter, range finding wheel, be arranged on the range finding wheel and go up magnetic group and Hall element or grating and photoelectric cell etc. and form.Range finding wheel is that the hawser of weight (6) drives by hanging, and comes absolute altitude at the bottom of the measured hole with measuring length that hawser walks.M is counted in the record hammering, and the output that the input of counter III (8-16) need only be connected to gating circuit (8-6) is the energy measurement and the hammering number that adds up.Testing process can be with hole depth 10cm be unit, mean oscillatory frequency f a, the fb of the every 10cm drilling process of detail record or mean oscillatory umber of pulse Na, Nb, indexs such as M, pore-forming rate of penetration Vh are counted in the accumulative total hammering, reach the purpose of continuous detecting, many index comprehensives are estimated the compressive strength of rock R and the structure of each rock stratum (7) and are held the otherness of levying.Pass average excited frequency fa, fb or average exciting umber of pulse Na, the Nb of each rock stratum (7) by analyzing pile foundation, indexs such as M, pore-forming rate of penetration Vh are counted in the accumulative total hammering, analyze the pile side friction and the stake end bearing capacity of each rock stratum (7), accurately calculate bearing capacity of pile foundation, determine the stake end whole hole absolute altitude, reach the purpose of safe and reliable and reasonable saving.
Of the present invention hold to levy be that sensor (3) can adopt hydrophone (12), booster-type piezoeletric quartz sensor (13) etc.Sensitivity, frequency band range, insulating properties and the water resistance of the sensor that requirement is adopted must satisfy actual instructions for use.Present technique adopts hydrophone, booster-type piezoeletric quartz sensor, and sensor placed pore-forming mud, have the effect of surface construction mechanical noise isolator, simultaneously because the filter action of mud, the shock response signal has only compressional wave to be left and is received at the bottom of making.
The present invention is directly applied for the stake bed rock differentiation of the pile foundation that adopts punching method pore-forming, adopts present technique can consider suitably to reduce geological drilling quantity.For the pile foundation that adopts rotary drill method pore-forming, can consider to use punching method continuation pore-forming instead behind the rock, or when carrying brill, also detect with little block stamp exciting.The little block stamp exciting of the whole appropriate to the occasion usefulness in hole of hand excavated pile is analyzed the pile bottom force holding layer situation.
Fig. 1 is a foundation pile end hole rock character detection method principle schematic.
Fig. 2 is a kind of foundation pile end hole rock character detector principle schematic.
Fig. 3 is two time-histories foundation pile end hole rock character detector principle schematic.
Fig. 4 is intelligent foundation pile end hole rock character detection method principle schematic.
Fig. 5 is multi-functional foundation pile end hole rock character detector principle schematic.
The present invention utilizes vibration to detect analytical instrument, sensor is placed in the mud of pile foundation pore-forming, detects at the bottom of the tension weight churning hole The rock stratum time shock oscillation ripple that sends, according to elastic collision theory and Mathematical Statistic Analysis Method, by analyzing the shock oscillation ripple Excited frequency fa, reach Information Evaluation and calculate the compressive strength of rock R of tested rock stratum, the qualitative analysis rock structure is held and is levied Otherness and the purpose of variation tendency, as the Main Basis that the whole hole of pile foundation absolute altitude is judged, have that principle is reliable, method is easy, The result is effect clearly quantitatively. The shock oscillation ripple is divided into two periods in time-histories, measures simultaneously the impulse excitation of rock stratum frequently Rate and strata structure forcing frequency or corresponding vibratory impulse number, it is poor further to improve rock strength and architectural feature The analysis Accuracy of Judgement of the opposite sex. It is simple that pile foundation stake end hole rock character detector has principle, and circuit is reliable and stable, the data place The reason digitized process, testing result is shown by counter that directly it is strong to have the circuit anti-interference ability, power saving, light excellent of structure The point. Be fit to numerous engineers and technicians and use, be conducive to Technique Popularizing. Detect by A/D converter and computer or microcomputer The waveform of storage shock oscillation ripple utilizes FFT technology etc. to analyze excited frequency fa, the vibration frequency fb of shock oscillation ripples; By The amplitude of vibrational waveform, the equal feature of shaking are judged the time tx that back wave arrives. According to the propagation law of elastic wave, can be more complete Structural feature and the othernesses such as the compressive strength of rock R of the tested rock stratum of surface analysis, bed thickness, weak intercalated layer, solution cavity, degree of crushing, For whole hole absolute altitude judgement at the bottom of the stake provides more scientific basis. Pile foundation pore-forming lithology test is simultaneously by hole depth measurement mechanism measured hole End absolute altitude, record hammering number, by detailed detection, record pore-forming pass through the mean oscillatory frequency of each rock stratum or average pulse number, The indexs such as accumulative total hammering number, pore-forming rate of penetration, can estimate more accurately each rock stratum compressive strength of rock R, pile side friction, Stake end bearing capacity and structure are held the otherness of levying. Accurately Single Pile Bearing is rationally determined the stake end whole hole absolute altitude, reaches safety Purpose reliable and that rationally save. Present technique adopts hydrophone, booster-type piezoeletric quartz sensor, and sensor is placed pore-forming In the mud, have simple installation, advantage that antijamming capability is strong.
Below in conjunction with drawings and Examples principle of the present invention and implementation method are further described.
Embodiment 1
As shown in Figure 1, certain bridge engineering, the geological conditions complexity, formation variation is frequent, the actual whole hole of the stake absolute altitude that has differs more than ten meter with the absolute altitude variation of the whole hole of design, and whole hole absolute altitude is judged difficulty, it has been decided through consideration that adopting foundation pile end hole rock character detector (8) to carry out lithology judges, reach the pile foundation pore forming process and can carry out the lithological information authentication purposes, whole hole absolute altitude can meet design requirement at the bottom of guaranteeing.
1. set up the corresponding relation of shock wave excited frequency fa and compressive strength of rock R
Select the representational pile foundation of geology to carry out the detailed spy of geology at the pile center place as test contrast stake.Requirement must be guaranteed the geological drilling quality of test pile, goes into behind the rock all many as far as possible samplings in every rock stratum and does the compressive strength of rock test.
Get each rock stratum core (high concentration slurry has attenuation to high-frequency sasser) in mud pit or clear water, make one iron hammer with the alloy steel material of making the block stamp tup, be used for surveying the umber of pulse of every hammer exciting, calculate corresponding vibration frequency at mud pit hammering core exciting.Adopt the average vibration frequency of each core, analyze its relation of corresponding compressive strength of rock R with it, as reference.
Test pile adopts the hole-punching method construction, directly detects weight (6) impinging earth strata (7) and sends the shock oscillation ripple, and the omnidistance situation of change that detects each rock stratum excited frequency fa is a unit with step pitch 10cm during detection, calculates its average vibration frequency and deviation value.In time analyze pore-forming and pass through the situation of change and the Changing Pattern of the excited frequency of each rock stratum process; Softer weak substratum (intensity is lower) is to the influence degree of rock stratum, upper strata etc.
For guaranteeing testing result accurately and reliably, following requirement is proposed for detection method and program:
1). require to make every hammer to fall apart from consistent impact machine clutch operational motion standard as far as possible.
2). sensor adopts hydrophone, in the outstanding as far as possible mud that is placed on pore forming process nearest safe place at the bottom of the hole.Should unify to be placed on: the stake end absolute altitude-(the block stamp maximum fall apart from+1m) locate.
3). whether to this testing result have interference, otherwise should suspend the drilling construction that faces stake when detecting less than 20m if should observe the drilling construction that faces stake of pilespacing about during detection.
4). be used for the hydraulic fill pipeline of hole deslagging clearly can not colligation at tup and hang the hawser that is, in order to avoid disturbance mud influence instrument operate as normal.
5). detection should implemented in the drilling process continuously.After stopping boring, the sediment that occurs at the bottom of the hole is influential to transmitting impact energy, and punching could be implemented normal the detection with after getting rid of sediment continuously.
6). during manual record, each rock stratum should be write down the above single hammer data of ten hammers at least, and other data can be that unit adds up and record automatically with per ten hammers, 20 hammers etc. by instrument.
7). should write down related datas such as rock scoriform attitude and pore-forming rate of penetration simultaneously.The otherness of in time finding the punch process testing result changes, and prevents to pass through suitable pile bottom force holding layer.
2. on-the-spot the detection implemented and judgement
The on-the-spot detection method and the program of pressing the test pile regulation of detecting implemented, and detection is analyzing and testing result's variation in time.The strength and stiffness of the high more representative of vibration frequency rock stratum are high more; The strength and stiffness of the low more representative of vibration frequency rock stratum are low more.Variation according to actual measurement excited frequency fa, with reference to the comparing result of test pile, probing report, rock slag, pore-forming rate of penetration etc., the compressive strength of rock R and the architectural feature of each roch layer interface of analysis and judgement, rock stratum, in time whether the checking computations bearing capacity of single pile meets design requirement, and whole hole absolute altitude drops on excited frequency the fa higher suitable rock stratum and absolute altitude at the bottom of should making as far as possible.
Design near the absolute altitude of whole hole to the stake end, when following situation occurring, should take seriously:
When 1) detecting such as excited frequency fa progressively reduce, if rate of penetration accelerates simultaneously, can be judged as rock strength and satisfy the step and reduce; If rate of penetration remains unchanged, can declare the substratum that exists this rock strength of strength ratio lower.Can meet the demands by friction pile checking computations bearing capacity of single pile, or pile foundation goes into the rock degree of depth and meet the demands substantially, should determine whole hole.
When 2) detecting such as excited frequency fa obviously reduce, with reference to rate of penetration, rock quarrel, can intend being judged as and pass through the rock stratum, situation such as interlayer occurs, should continue punching.
When 3) detecting such as excited frequency fa reduce suddenly.Can intend being judged as and break through the higher rock stratum of intensity, should seek new rock stratum that can whole hole.
When 4) detecting such as the deviation value of excited frequency fa increase, can intend being judged as the rock stratum serious broken, the rock qualitative changeization is big, should be in conjunction with probing report and bearing capacity of pile foundation checking computation results, whether decision continues to creep into.
When 5) excited frequency fa is seriously discrete, can intend being judged as states such as appearance half native half rock, should continue punching, and notice that situations such as inclined hole, card hammer appear in prevention.
Foundation pile end hole rock character detector (8) as shown in Figure 2, amplifying circuit (8-1) operating frequency range is 10Hz-10kHz, time base circuit (8-4) adopts the quartz oscillator of high stability as vibration source, shaping circuit (8-2), trigger (8-3), frequency divider (8-5), gating circuit (8-6), gate circuit (8-7) etc. adopt the high-speed cmos discrete component to constitute, to improve the operating rate of instrument.Circuit triggers startup work certainly by the Mintrop wave of shock oscillation ripple, and sampling time length is selected mainly to detect exciting and involve its repercussions between the 0--1ms to 0--10ms.Display (9-9) adopts LCD, is convenient to work in the sun, and single hammer testing result demonstration time is no less than 3S.
Shown in accompanying drawing 1 and accompanying drawing 3, adopt foundation pile end hole rock character detector (8) and booster-type piezoeletric quartz sensor (13).The shock oscillation ripple is divided into main reflection percussion excitation phase and two periods of strata structure forced vibration stage on time-histories, first period of this example gets 0-10ms, second period and gets 10-60ms, measures exciting umber of pulse Na and the vibratory impulse of two periods respectively and counts Nb.Exciting umber of pulse Na and vibratory impulse are counted Nb respectively by counter (8-8) and display (8-9), counter II (8-14) and display II (8-15) counting and demonstration.For reducing the influence of exciting repercussions to second time-histories, wave filter (8-10) is designed to low pass filter, and the filtering cut-off frequency is got about 2kHz.
Can judge the holding property of rock stratum according to the relationship analysis of actual measurement excited frequency fa and vibration frequency fb:
1) strength and stiffness of the high more representative of excited frequency fa rock stratum are high more; The strength and stiffness of the low more representative of excited frequency fa rock stratum are low more;
2) the high more representative of vibration frequency fb is thin more; The low more representative of vibration frequency fb rock stratum is thick more;
When 3) excited frequency fa and vibration frequency fb are higher, can intend judging that tested rock strength height, globality are better, substratum is also better, but the rock stratum is thinner;
4) excited frequency fa is higher and vibration frequency fb is lower, and during the testing result good reproducibility, can intend being judged as tested rock stratum is intensity height, globality rock stratum preferably;
5) excited frequency fa is lower and vibration frequency fb is higher, and during the testing result good reproducibility, can intend being judged as that tested rock strength is lower, layer is thin, and substratum intensity is relatively poor;
When 7) excited frequency fa and vibration frequency fb are low simultaneously, can intend judging that tested rock strength is lower or soft sleeper interlayer etc. is arranged;
8) excited frequency fa and vibration frequency fb are higher and the deviation value is bigger, can intend judging tested strata structure fragmentation, and substratum is better relatively;
9) excited frequency fa and vibration frequency fb deviation value are big, and the testing result poor repeatability can intend judging that tested rock stratum rock qualitative changeization is big.
All the other are as embodiment 1.
Embodiment 3
As shown in Figure 4, detection of dynamic instrument (1) detects the waveform of storage shock oscillation ripple by A/D converter (9) and computer or microcomputer (10), utilize excited frequency fa, the vibration frequency fb etc. of analysis shock oscillation ripples such as FFT technology, judge the tx time of advent of back wave by the amplitude of vibrational waveform, the equal feature of shaking.According to the propagation law of elastic wave, comprehensively calculate the compressive strength of rock R of tested rock stratum (7), analyze the lift height hx of rock stratum, prevent that pile-base supporting layer from can not meet design requirement.Detecting instrument is a digitized instrument that general dynamic amplifier, A/D converter and microcomputer are combined.
The shock oscillation ripple directly reflects the structural feature of rock stratum, and waveform analysis can be judged in conjunction with following rule:
1) incident wave height, back wave is faint, and back wave is long the time of advent, and it is firm reliable to be judged as the bearing stratum basement rock;
2) if clear, the good reproducibility of back wave waveform can be judged the rock stratum good integrity, the intensity height;
3) as if the disorder of back wave waveform, but good reproducibility, it is many to intend being judged as interlayer;
4) if the disorder of back wave waveform, decay is fast, and poor repeatability, can intend being judged as crushing rock formation or the rock qualitative changeization is big;
When 5) back wave is the homophase reflected signal, represent the rock strength following for sleeping in of tested rock stratum lower;
When 6) back wave is the homophase reflected signal, and repeatedly orderly reflection wave signal occurs, can intend being judged as and have serious soft sleeper layer or a solution cavity etc.;
When 7) back wave was anti-phase reflected signal, the rock strength following for sleeping in of representing tested rock stratum was than higher.
According to the propagation law of elastic wave, in time-domain analysis, can determine the time of advent of back wave according to features such as the wave amplitude of back wave, phase places, utilize back wave the time of advent tx and velocity of wave c calculate the bed thickness hx of tested rock stratum by following formula:
hx＝1/2·tx·c
Each class surrounding rock longitudinal wave velocity c is about 3000m/s-6000m/s.
According to the propagation law of elastic wave, in frequency-domain analysis, utilize FFT technology etc. to carry out spectrum analysis, determine excited frequency fa, the vibration frequency fb of shock oscillation ripple.Utilize vibration frequency fb and velocity of wave c to calculate the bed thickness hx of tested rock stratum by following formula:
hx＝1/2·c/fb
All the other are as embodiment 2.
Shown in accompanying drawing 3, accompanying drawing 5, adopt multi-functional pile foundation lithology authentication technique.Increase counter III (8-16) and display III (8-17) and write down hammering and count M in foundation pile end hole rock character detector (8), increase hole depth measuring equipment (11) comes absolute altitude at the bottom of the measured hole.Pass through the average pulse of each rock stratum by the analysis pore-forming and count Na, Nb, indexs such as M, pore-forming rate of penetration Vh are counted in the accumulative total hammering, and compressive strength of rock R of each rock stratum of analysis-by-synthesis (7) and structure are held the otherness of levying.Hole depth measuring equipment (11) by forward-backward counter, range finding wheel, be arranged on grating on the range finding wheel and photoelectric cell etc. and form, depth survey resolution ratio is 1cm.Range finding wheel is that the hawser of weight (6) drives by hanging, and comes absolute altitude at the bottom of the measured hole with the walking length of measurement hawser.The input of counter III (8-16) is connected to the output of gating circuit (8-6), counts M by the hammering of accumulative total gating pulse number scale record.
Be unit with hole depth 10cm in the testing process, average exciting umber of pulse Na, the Nb of the every 10cm drilling process of meter record in detail, indexs such as M, pore-forming rate of penetration Vh are counted in the accumulative total hammering, analyze the pile side friction and the stake end bearing capacity of each rock stratum (7).The palm pile capacity that calculates when the foundation testing result can meet design requirement, and confirms the no abnormal situation of pile bottom force holding layer, promptly determines the whole hole of pile foundation.
All the other are as embodiment 1.
In the pile foundation construction manufacturing process, press embodiment 1 or embodiment 2 methods by engineers and technicians and implement,, adopt method enforcements such as embodiment 3 by full-time engineer when running into to resolve with embodiment 1 or embodiment 2 methods the time.
Claims (7)
1. the method for foundation pile end hole rock character detection and judgment technique of the present invention, it is characterized in that detection of dynamic instrument (1) is placed to sensor (3) by lead (2) in the mud (5) of pore-forming (4) of pile foundation, the excited frequency fa of the shock oscillation ripple that sends in the time of on the scar of the rock stratum (7) at the bottom of detection weight (6) impact opening, or exciting umber of pulse Na, according to the elastic collision theory, by analyzing the excited frequency fa of shock oscillation ripple, or the dependency relation of the compressive strength of rock R of exciting umber of pulse Na and rock stratum (7), thereby calculate the compressive strength of rock R of tested rock stratum (7), as the main foundation of the whole hole of pile foundation absolute altitude judgement.
2. according to claim 1, the special-purpose detection of dynamic instrument (1) that a kind of foundation pile end hole rock character detector of the present invention (8) detect to be differentiated as foundation pile end hole rock character, it is held to levy and is that foundation pile end hole rock character detector (8) is made up of amplifying circuit (8-1), shaping circuit (8-2), trigger (8-3), time base circuit (8-4), frequency divider (8-5), gating circuit (8-6), gate circuit (8-7), counter (8-8), display (8-9) etc.The output of amplifying circuit (8-1) is connected respectively to the input of shaping circuit (8-2) and the input of trigger (8-3), the output of trigger (8-3) is connected respectively to the reset terminal of frequency divider (8-5) and the set end of gating circuit (8-6), the input of frequency divider (8-5) and output are connected respectively to the output of time base circuit (8-4) and the reset terminal of gating circuit (8-6), the output of gating circuit (8-6) is connected to the control end of gate circuit (8-7), the input of gate circuit (8-7) and output are connected respectively to the input of the output sum counter (8-8) of shaping circuit (8-2), and the output of counter (8-8) connects the input of display (8-9).
3. according to claim 1, of the present invention hold to levy be the shock oscillation ripple is divided into main reflection rock stratum (7) percussion excitation phase and two periods of structure forced vibration stage on time-histories, measure and analyze excited frequency fa and the vibration frequency fb of two periods respectively, or exciting umber of pulse Na and vibratory impulse in above-mentioned two periods are counted Nb, variation and relation that excited frequency fa by analyzing two periods and vibration frequency fb or exciting umber of pulse Na and vibratory impulse are counted Nb are calculated the compressive strength of rock R of rock stratum (7) and are analyzed the otherness of rock stratum (7) structural feature.
4. as described in the claim 2, it holds a kind of foundation pile end hole rock character detector of the present invention (8) to levy and is that foundation pile end hole rock character detector (8) has increased wave filter (8-10), shaping circuit II (8-11), gating circuit II (8-12), gate circuit II (8-13), counter II (8-14), display II circuit such as (8-15).The input of wave filter (8-10) and output are connected respectively to the output of amplifying circuit (8-1) and the input of shaping circuit II (8-11), the set end of gating circuit II (8-12), reset terminal, output is connected respectively to the output of gating circuit (8-6), another output of frequency divider (8-5), gate circuit II (8-13) control end, the input of gate circuit II (8-13) and output are connected respectively to the input of the output sum counter II (8-14) of shaping circuit II (8-11), and the output of counter II (8-14) is connected to display II (8-15) input.
5. according to claim 1, of the present invention hold to levy be that detection of dynamic instrument (1) detects the waveform of storage shock oscillation ripple by A/D converter (9) and computer or microcomputer (10), utilize excited frequency fa, the vibration frequency fb etc. of analysis shock oscillation ripples such as FFT technology, judge the tx time of advent of back wave by the amplitude of vibrational waveform, the equal feature of shaking, according to the propagation law of elastic wave, structural feature and othernesses such as the compressive strength of rock R of the tested rock stratum of analysis-by-synthesis (7), lift height hx.
6. according to claim 1, of the present invention hold to levy be simultaneously by absolute altitude at the bottom of hole depth measurement mechanism (11) measured hole, in foundation pile end hole rock character detector (8), increase counter III (8-16) and display III (8-17), and the output that is connected to gating circuit (8-6) is used to write down hammering and counts M, by analyzing mean oscillatory frequency f a, fb or mean oscillatory umber of pulse Na, the Nb that pore-forming passes through each rock stratum (7), indexs such as M, pore-forming rate of penetration Vh are counted in the accumulative total hammering, and compressive strength of rock R of each rock stratum of analysis-by-synthesis (7) and structure are held the otherness of levying.
7. according to claim 1, of the present invention hold to levy be that sensor (3) can adopt hydrophone (12), booster-type piezoeletric quartz sensor (13) etc.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200510037064 CN1928260A (en) | 2005-09-08 | 2005-09-08 | Method for foundation pile end hole rock character detection and judgment technique |
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| CN 200510037064 CN1928260A (en) | 2005-09-08 | 2005-09-08 | Method for foundation pile end hole rock character detection and judgment technique |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102071705A (en) * | 2010-11-11 | 2011-05-25 | 河北建设勘察研究院有限公司 | Non-destructive detection method for pile bottom karst |
| CN105223274A (en) * | 2015-09-29 | 2016-01-06 | 鞍钢集团矿业公司 | Utilize in hole the method for the detecting rock equivalent elastic modulus that drops hammer |
| CN108593769A (en) * | 2018-03-05 | 2018-09-28 | 四川升拓检测技术股份有限公司 | Utilize the normalized signal exciting lossless detection method of multi-way contral elastic wave |
| CN109655338A (en) * | 2018-12-13 | 2019-04-19 | 深圳宏业基岩土科技股份有限公司 | The method for controlling rock-socketed piles quality |
| CN110219298A (en) * | 2019-05-14 | 2019-09-10 | 广东省交通规划设计研究院股份有限公司 | A kind of construction Punching Borehole Cast-in-place Concrete Pile formation parameter determines method |
| CN111158043A (en) * | 2020-01-07 | 2020-05-15 | 中南大学 | System and method for detecting hidden danger at pile bottom of bored pile |
| CN114000548A (en) * | 2021-09-30 | 2022-02-01 | 深圳市房屋安全和工程质量检测鉴定中心 | Foundation pile rock-socketed depth detection method based on sound wave method |
-
2005
- 2005-09-08 CN CN 200510037064 patent/CN1928260A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102071705A (en) * | 2010-11-11 | 2011-05-25 | 河北建设勘察研究院有限公司 | Non-destructive detection method for pile bottom karst |
| CN105223274A (en) * | 2015-09-29 | 2016-01-06 | 鞍钢集团矿业公司 | Utilize in hole the method for the detecting rock equivalent elastic modulus that drops hammer |
| CN108593769A (en) * | 2018-03-05 | 2018-09-28 | 四川升拓检测技术股份有限公司 | Utilize the normalized signal exciting lossless detection method of multi-way contral elastic wave |
| CN108593769B (en) * | 2018-03-05 | 2020-08-11 | 四川升拓检测技术股份有限公司 | Normalized signal excitation nondestructive testing method by using multichannel control elastic wave |
| CN109655338A (en) * | 2018-12-13 | 2019-04-19 | 深圳宏业基岩土科技股份有限公司 | The method for controlling rock-socketed piles quality |
| CN110219298A (en) * | 2019-05-14 | 2019-09-10 | 广东省交通规划设计研究院股份有限公司 | A kind of construction Punching Borehole Cast-in-place Concrete Pile formation parameter determines method |
| CN110219298B (en) * | 2019-05-14 | 2021-08-24 | 广东省交通规划设计研究院股份有限公司 | Construction punching cast-in-place pile stratum parameter determination method |
| CN111158043A (en) * | 2020-01-07 | 2020-05-15 | 中南大学 | System and method for detecting hidden danger at pile bottom of bored pile |
| CN111158043B (en) * | 2020-01-07 | 2021-09-17 | 中南大学 | System and method for detecting hidden danger at pile bottom of bored pile |
| CN114000548A (en) * | 2021-09-30 | 2022-02-01 | 深圳市房屋安全和工程质量检测鉴定中心 | Foundation pile rock-socketed depth detection method based on sound wave method |
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