CN115929326B - Reinforced construction method for crossing tunnel of water-rich fault fracture zone - Google Patents

Abstract

The invention relates to a reinforcement construction method for crossing a water-rich fault fracture zone tunnel. Determining a first detection result by utilizing a first group of detection strategies in a first detection range which is separated from a construction working surface of a tunnel by a first detection distance, wherein the first detection result indicates first-level geological information associated with an abnormal section in the first detection range, and the abnormal section comprises a water-rich fault fracture zone; detecting the abnormal section by utilizing a second group of detection strategies in a second detection range to obtain a second detection result, wherein the second detection result indicates second-level geological information associated with the abnormal section, and the second detection distance is smaller than the first detection distance; and selecting a preset grouting mode from a group of preset grouting modes aiming at the abnormal sections based on the first detection result and the second detection result, and grouting and reinforcing one or more abnormal sections. In this way, the fault and water-rich condition along the tunnel can be dynamically monitored, and the reinforcement scheme can be timely adjusted, so that the tunnel construction safety is ensured.

Description

Reinforced construction method for crossing tunnel of water-rich fault fracture zone

Technical Field

The present invention relates generally to the field of construction technology, in particular to the field of mountain tunnel construction technology, and more particularly to a reinforced construction method for traversing a water-rich fault fracture zone tunnel.

Background

With the rapid development of the construction of the traffic infrastructure in China, more and more highway and railway mountain tunnels appear successively. The roller tunnels encounter various complex geological conditions such as karst, faults and the like during the crossing process. Faults refer to structures in which the crust is broken under stress and rock masses on two sides of a broken surface are subjected to remarkable relative displacement. The fault scales are different, but the continuity and the integrity of the rock stratum are damaged, the rock is often broken on a fault zone, surrounding rock is loose, cracks develop, and geological disasters such as collapse, roof fall, water burst, mud burst and the like are easily caused.

The occurrence of water bursting and mud bursting of the fault fracture zone has extremely strong destructive effect on the tunnel, the construction difficulty of the tunnel penetrating through the water-rich fault fracture zone is large, for example, the position of the fault is difficult to accurately determine, and the water bursting disaster is caused by the insufficient excavation disturbance and supporting strength of the tunnel. In the current scheme, the detection of geological conditions only depends on conventional means such as geological investigation, but the means cannot detect specific information such as the position, the property, the scale, the water-rich condition and the like of faults. And with the promotion of working face, the mechanical parameter and the rich water condition of fault also can change, and the geological survey of static nature can't satisfy the requirement of dynamic construction, brings very big construction potential safety hazard.

The current geological exploration technology only depends on the conventional geological exploration means, the fault position is difficult to accurately determine, and tunnel excavation disturbance and supporting strength cannot be accurately and dynamically predicted. And with the dynamic promotion of construction operation face, the mechanical parameter and the rich water condition of fault can change, and current scheme water detection ability is not enough, can not satisfy fault and rich water and explore and follow-up slip casting reinforcement's requirement dynamically, therefore the technician can not adjust the reinforcement scheme in tunnel construction in-process dynamically, brings very big inconvenience and potential safety hazard for the construction.

Therefore, a dynamic and accurate forecasting system is urgently needed, and grouting water shutoff schemes are selected in a targeted mode and dynamically adjusted, so that the construction period is shortened, and the construction safety is guaranteed.

Disclosure of Invention

The invention aims to provide a reinforcement construction method for traversing a water-rich fault fracture zone tunnel, so as to at least partially solve the problems in the prior art.

According to a first aspect of the invention, a reinforcement construction method for traversing a water-rich fault zone tunnel is provided. The method comprises the following steps: determining a first detection result by utilizing a first group of detection strategies in a first detection range which is separated from a construction working surface of the tunnel by a first detection distance, wherein the first detection result indicates first-level geological information associated with one or more abnormal sections in the first detection range, and one or more abnormal sections comprise the water-rich fault fracture zone; detecting one or more of the anomaly segments with a second set of detection strategies within a second detection range of a second detection distance from a construction face of the tunnel to obtain a second detection result, wherein the second detection result is indicative of second-level geological information associated with one or more of the anomaly segments, and wherein the second detection distance is less than the first detection distance; selecting one or more preset grouting modes from a group of preset grouting modes for one or more abnormal sections based on the first detection result and the second detection result; and grouting and reinforcing one or more abnormal sections by using one or more preset grouting modes.

In some embodiments, the method further comprises: determining whether to detect within a third detection range from a construction working face of the tunnel by a third detection distance based on the first detection result and the second detection result, wherein the third detection distance is smaller than the second detection distance; detecting one or more of the anomalous segments with a third set of detection strategies upon determining that detection is to be within the third detection range to obtain a third detection result, wherein at least one strategy of the third set of detection strategies is different from a strategy of the second set of detection strategies and the third detection result indicates third-level geological information associated with one or more of the anomalous segments; and selecting one or more preset grouting modes based on the first detection result, the second detection result and the third detection result.

In some embodiments, the detection accuracy of the first level of geologic information is less than the detection accuracy of the second level of geologic information, and/or the detection accuracy of the second level of geologic information is less than the detection accuracy of the third level of geologic information.

In some embodiments, the method further comprises: performing deformation monitoring and hydrologic monitoring on one or more abnormal sections reinforced by grouting; wherein said deformation monitoring of one or more of said anomaly segments reinforced by grouting comprises: performing vault subsidence and convergence measurement on the tunnel, wherein the distance between measuring points for the vault subsidence and convergence measurement is positively correlated with the surrounding rock level of one or more abnormal sections; and wherein said hydrologic monitoring of said one or more reinforced by grouting of said anomaly segments comprises: a hydrographic variation parameter for one or more of the anomaly segments is determined, and an alert threshold, a hazard threshold, and a control threshold are set based on the hydrographic variation parameter, wherein the alert threshold, the hazard threshold, and the control threshold are each associated with a different remedial action.

In some embodiments, the method further comprises: carrying out a pressurized water test on one or more abnormal sections in the grouting construction process; and when the water permeability of one or more abnormal sections is determined to be smaller than a preset threshold value, re-grouting the one or more abnormal sections until the strength of the one or more abnormal sections reaches a design value.

In some embodiments, the first set of detection strategies includes one or more of a survey data verification method, a TSP method, and a transient electromagnetic method; the second set of detection strategies includes one or more of a geological radar method, an induced polarization method, and a advanced horizontal drilling method; and the third set of detection strategies includes one or more of deepening borehole detection, induced polarization, advanced horizontal drilling, geological radar, geological sketching.

In some embodiments, the first detection distance is not less than 100 meters, the second detection distance is not greater than 80 meters, and the third detection distance is not greater than 40 meters.

In some embodiments, the method further comprises: judging the water-rich position of one or more abnormal sections by adopting a transient electromagnetic method; and determining a three-dimensional image of the water-rich position and the water volume by using an induced polarization method.

In some embodiments, the set of preset grouting modes includes one or more of full face advanced grouting, peripheral curtain pre-grouting, radial grouting, partial grouting; the full-section advanced grouting is carried out from the outer ring to the inner ring in a sectional advancing manner and hole separation encryption is carried out; the peripheral curtain pre-grouting adopts forward type sectional grouting, and sequentially comprises the steps of firstly grouting an outer ring hole, then grouting an inner ring hole, finally grouting an intermediate ring hole, and performing hole isolation encryption; the radial grouting and the local grouting adopt disposable grouting.

In some embodiments, the method further comprises: carrying out regression analysis on the detection information obtained by the deformation monitoring and the hydrologic monitoring to obtain a deformation regression equation; acquiring displacement related information for one or more abnormal segments based on the deformation regression equation; and feeding back the displacement related information to a construction site, and optimizing a construction scheme in time.

The embodiments of the invention have at least the following beneficial effects:

(1) By means of multi-stage advanced detection, whether faults exist or not, the positions, the properties and the scale of the faults and the water containing conditions of the faults are determined step by step, and resource waste caused by excessive reinforcement and safety accidents caused by insufficient reinforcement are effectively avoided.

(2) In the tunnel excavation process, the mechanical property and the hydraulic property of the rock mass can be changed, and according to the scheme provided by the invention, the geological condition in front of a construction working face (also called a tunnel face) can be dynamically detected, and the construction scheme can be timely adjusted.

(3) The multi-stage advanced prediction gradually increases the detection precision along with the detection range from far to near, and can detect more kinds of target objects, thereby being beneficial to dynamically adjusting the reinforcement scheme and taking targeted reinforcement measures.

(4) By means of advanced prediction, the grouting water shutoff scheme is directionally implemented, rapid construction is facilitated, and cost is saved.

(5) The transient electromagnetic method and the induced polarization method (TIP method) are combined to detect the front water distribution characteristics, the water content position is firstly judged preliminarily through the transient electromagnetic method, and then the problem of positioning of the water content structure in the tunnel construction period can be effectively solved through the combination of the TIP method, three-dimensional imaging of the water content body and water quantity judgment are achieved, and the water detection capacity in geological forecast is improved.

It should be understood that the description in this summary is not intended to limit the critical or essential features of the embodiments of the invention, nor is it intended to limit the scope of the invention. Other features of the present invention will become apparent from the description that follows.

Drawings

The above, as well as additional purposes, features, and advantages of embodiments of the present invention will become apparent in the following detailed written description and claims upon reference to the accompanying drawings. Several embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which:

FIG. 1 is a schematic diagram of a combination scheme of prediction strategies according to an exemplary embodiment of the present invention;

FIG. 2 is a schematic flow chart of an overall reinforcement construction scheme according to an exemplary embodiment of the present invention;

FIG. 3 is an engineering schematic diagram of a full face grouting method according to an exemplary embodiment of the present invention;

FIG. 4 is a schematic diagram of an orifice arrangement employing full face grouting in accordance with an exemplary embodiment of the present invention, wherein (a) - (D) represent sections A-A through D-D, respectively;

FIG. 5 is an engineering schematic drawing of a peripheral curtain grouting method according to an exemplary embodiment of the present invention;

FIG. 6 is a schematic diagram of an orifice arrangement employing a peripheral curtain grouting approach according to an exemplary embodiment of the present invention, wherein (a) - (D) represent sections A-A through D-D, respectively;

fig. 7 is a schematic view of a cross-sectional arrangement employing a radial grouting method according to an exemplary embodiment of the present invention, wherein (a) represents a cross section and (b) represents a longitudinal section;

FIG. 8 is a schematic illustration of a fracture water grouting in a localized grouting mode, wherein (a) represents a longitudinal section and (b) represents A-A section, according to an exemplary embodiment of the present invention;

fig. 9 is a schematic view of planar water out grouting using a partial grouting method according to an exemplary embodiment of the present invention.

Like or corresponding reference characters indicate like or corresponding parts throughout the several views.

Detailed Description

Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While the invention is susceptible of embodiment in the drawings, it is to be understood that the invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but rather are provided to provide a more thorough and complete understanding of the invention. It should be understood that the drawings and embodiments of the invention are for illustration purposes only and are not intended to limit the scope of the present invention.

In describing embodiments of the present invention, the term "comprising" and its like should be taken to be open-ended, i.e., including, but not limited to. The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first," "second," and the like, may refer to different or the same object. Other explicit and implicit definitions are also possible below.

In this context, "construction work surface" and "face" express the same or similar concepts and are thus capable of substitution in context. In some specific scenarios, "prediction" and "forecast" express the same or similar concepts, and thus can be substituted in context.

As mentioned before, during the construction process of tunnel crossing the water-rich fault fracture zone, the current geological exploration only depends on the conventional geological exploration means, the fault position is difficult to accurately determine, and the tunnel excavation disturbance and the support strength cannot be accurately and dynamically predicted. And along with the dynamic promotion of construction operation face, the mechanical parameters and the rich water condition of fault can change, and current scheme can not satisfy fault and rich water and explore and follow-up slip casting reinforcement's requirement dynamically, can not adjust the reinforcement scheme dynamically in tunnel construction process, brings very big inconvenience and potential safety hazard for the construction.

At least aiming at the problems, the invention provides a comprehensive, accurate and dynamic advanced forecasting scheme, emphasizes a comprehensive forecasting method of combining geological investigation analysis with physical detection, combining structure detection with water detection and combining middle-long distance forecasting with short distance forecasting, and before tunnel excavation, carries out geological forecasting on geological conditions in front of the tunnel, deduces basic information such as geological conditions in the tunneling direction of a construction working face, and the like, carries out forecasting and early warning on the engineering geology in front through advanced geological forecasting, judges whether surrounding rock needs water shutoff grouting or not, selects which method to carry out, prevents water burst from causing safety accidents and influences construction progress. Relevant personnel give corresponding technical measures and feasibility suggestions according to the prediction result, so that the construction safety of tunnel engineering can be effectively ensured, and obvious economic benefits are obtained.

An exemplary embodiment of the present invention will be described in detail with reference to fig. 1 to 9.

Fig. 1 is a schematic diagram of a prediction strategy combining scheme according to an exemplary embodiment of the present invention. In some embodiments, a first detection result is determined using a first set of detection strategies over a first detection range of a first detection distance from a construction face of the tunnel, the first detection result indicating first-level geological information associated with one or more anomalous sections in the first detection range, wherein the one or more anomalous sections comprise a water-rich fault zone. As shown in fig. 1, the construction working surface may be a face surface, the first detection distance may be not less than 100 meters, and the first set of detection strategies may be, for example, one or more of a geological survey verification method, a TSP method, and a transient electromagnetic method. The first-level geological information may be, for example, first-level geological information associated with a water-rich fault zone, wherein the one or more anomaly segments include a surrounding rock category, a location, a nature, a scale, and a geological water-rich condition of the fault zone, among others. In this way, the first set of detection strategies can be used to make long-term predictions or long-range predictions.

In some embodiments, the survey data verification method may obtain preliminary geological conditions along the tunnel by querying preliminary geological survey results of the zone along the tunnel. The geological survey data verification method can comprise, for example, data of geological survey of the ground along the tunnel, that is, the geological survey of the ground along the tunnel can be used to obtain the preliminary geological condition. It should be appreciated that the survey data verification method may detect distances of 100 meters and more from the construction work surface, and may also detect geological conditions along the tunnel near the construction work surface, as the invention is not limited in this regard.

The TSP method, a tunnel seismic wave prediction method, is based on the principle that a seismic wave signal generated by small-dose blasting propagates in the form of spherical waves in the tunnel direction, and seismic waves propagate at different speeds in different rock layers, are reflected at interfaces thereof, and are received by high-precision receivers. The characteristics of surrounding rock, joint fracture distribution, weak rock stratum, water content and the like in front are analyzed through computer software, the angle which is presented by the intersection of various surrounding rock structural interfaces and tunnel axes and the distance from the tunnel face are displayed on a final display screen, and parameters such as the elastic modulus, density, poisson ratio and the like of the rock can be preliminarily measured for reference. In some embodiments, referring to fig. 1, when TSP203 method may be used for long-term prediction, the prediction distance under hard rock condition may reach 150m to 200m, and the prediction accuracy of the fault fracture zone structure is high, so as to primarily determine the surrounding rock category, the position, the property, the scale and the like of the fault fracture zone.

Transient electromagnetic methods can utilize ungrounded return or ground line sources to emit primary pulsed magnetic fields into the subsurface, and during the primary pulsed magnetic field pauses, secondary eddy fields are observed with coils or ground electrodes. Briefly, the basic principle of transient electromagnetic methods is the law of electromagnetic induction. The attenuation process is generally divided into early, middle and late stages. The early electromagnetic field is equivalent to high-frequency components in the frequency domain, the attenuation is fast, and the skin depth is small; the late component is equivalent to the low frequency component in the frequency domain, the attenuation is slow, and the skin depth is large. And by measuring the change rule of the secondary field of each time period along with time after power failure, the ground electric characteristics of different depths can be obtained. In some embodiments, referring to fig. 1, the forecast distance may be about 100m for long-term forecast using transient electromagnetic methods, to evaluate the richness of the tunnel to be reinforced along the line.

In a specific embodiment, TSP203 method, transient electromagnetic method and geological survey data may be used to determine the surrounding rock condition within 100 meters ahead, to form a first detection result, and to primarily determine the geological condition ahead. In this embodiment, specifically, the dangerous area and the important paragraph can be preliminarily divided in combination with the geological survey data, and geological disasters which may occur during the construction process can be predicted. Long-distance and large-range forecasting, such as surrounding rock classification, fault fracture zone position, property and scale, is carried out through a TSP method, stratum boundaries are divided, geological structures are searched, and the thickness and range of poor geology are detected. And then the transient electromagnetic method is combined to evaluate the front water enrichment. Through long-distance forecasting, the hidden serious geological problems which are difficult to explore due to the limitation of early geological exploration work can be further cleared, and a prevention scheme is determined to guide subsequent construction.

In some embodiments, the one or more anomalous sections are detected with a second set of detection strategies within a second detection range of a second detection distance from the construction work surface of the tunnel to obtain a second detection result, wherein the second detection result is indicative of second-level geological information associated with the one or more anomalous sections, and wherein the second detection distance is less than the first detection distance. As shown in fig. 1, the second detection distance may be no greater than 80 meters, and the second set of detection strategies may be, for example, one or more of a geological radar method, an induced polarization method, and a look-ahead horizontal drilling method. The second-level geological information may be geological information with higher accuracy than the first-level geological information, may contain geological information of a different object from the first-level geological information, and may have a detection range different from the first-level geological information. In other words, the first-level geological information and the second-level geological information may be different in information accuracy, detection objects, detection ranges, and the like, but may include the same type of geological information. In this way, the second set of detection strategies can be used to make mid-to-long range predictions or mid-range predictions.

Deep hole exploration is an important method for acquiring accurate geological data below the earth surface, and deep hole drilling work is required to be carried out on the basis of engineering ground quality survey and geophysical prospecting work. The deep hole drilling aims to verify deep stratum sequence, lithology and rock mass integrity, determine the position, width and breaking degree of faults in the deep part and verify geophysical prospecting abnormal properties. The advanced horizontal drilling method is to place a horizontal drilling machine in the tunnel to carry out horizontal drilling, and deduce geological conditions in front of the tunnel according to drilling data. The number, angle and depth of the holes can be designed and controlled manually. Forecasting was performed based on changes in drilling speed, borehole coring identification, borehole flushing fluid color, odor rock dust, and other conditions encountered. Because the advanced drilling can most directly reveal the geological features in front of the face, the accuracy is higher

In some embodiments, as shown in FIG. 1, the advanced horizontal drilling method may make mid-term predictions, which may be, for example, 40m to 80m. The advanced horizontal drilling method is used for physical detection, and the accurate position of fault can be directly found.

The geological radar method transmits high-frequency narrow pulse electromagnetic waves generated by a radar instrument to the earth through an antenna, the propagation speed and attenuation rate of the electromagnetic waves in the earth depend on the dielectric property and the conductivity of rock, the electromagnetic waves are very sensitive to the change of rock type and the water content of cracks, and partial transmission waves can be reflected once the conductive property of the rock changes in the propagation process. The receiver detects the reflected signal or the direct transmitted signal, amplifies and digitizes it, and stores it on a digital tape recorder for data processing and display. In some embodiments, as shown in fig. 1, the geological radar method may make mid-to-short term predictions, and the forecast distance may be 10m to 40m. In this way, the fault fracture zone prediction accuracy is high, the range is narrow, and the construction interference is small.

Induced polarization (also called TIP) is a type of electrical exploration method based on differences in the excitation effects of rock and ore, which is used to explore subsurface geologic conditions or solve some hydrogeologic problems by observing and studying the earth excitation effects, and is characterized in that polarized units (tiny metallic minerals or rock particles) are physically distributed throughout the polarizer. Under the excitation of external current, the specimen becomes cathode at the current inflow end, generates cathode polarization, and becomes anode at the current outflow end, so that the water-rich characteristic distribution can be predicted. In some embodiments, as shown in FIG. 1, induced polarization can be used for mid-to-short term prediction, and the prediction distance can be 0-30m to accurately predict the water distribution characteristics of the surrounding rock in front of the work surface.

In a specific embodiment, if the first detection result is normal, normal working surface excavation can be performed, and for abnormal sections, medium-short distance prediction is performed to form a second detection result, the first detection result is verified, and the geological condition in front is further determined. The geological radar, the TIP method and the advanced horizontal drilling method are adopted to further detect abnormal sections, and the geological radar and the TIP method can further detect the geological conditions in front to determine the water-rich condition or the rock mechanical property. By combining an advanced horizontal drilling method, the geological condition in front can be directly known, and the fault position can be accurately found.

In some embodiments, based on the first detection result and the second detection result, it is determined whether to detect within a third detection range of a third detection distance from a construction work surface of the tunnel, wherein the third detection distance is less than the second detection distance, and when it is determined that detection is to be within the third detection range, one or more anomalous sections are detected with a third set of detection strategies to obtain a third detection result, wherein at least one strategy of the third set of detection strategies is different from a strategy of the second set of detection strategies, and the third detection result indicates third-level geological information associated with the one or more anomalous sections. As shown in fig. 1, the third detection distance may be not less than 40 meters, and the third set of detection strategies may be, for example, one or more of deepening borehole detection, induced polarization, advanced horizontal drilling, geological radar, geological sketching. The third level of geological information may be, for example, the occurrence, location, scale, water-rich conditions of the fault, the impact on the project, etc. In one embodiment, the induced polarization method and the geological radar method may be used for the second set of detection strategies at the same time, but may differ in detection object, detection accuracy, and detection distance. In this way, the third set of detection strategies can be used to make short range predictions or short term predictions.

In some embodiments, the first, second, and third sets of detection policies may include one or more of the same policies. For example, the first set of detection strategies, the second set of detection strategies, and the third set of detection strategies may all include advanced horizontal drilling or any other suitable strategy. This is because reinforcement means are diverse, and reinforcement can take a variety of viable strategies for different geological conditions. Meanwhile, the first group of detection strategies, the second group of detection strategies and the third group of detection strategies can comprise different strategies based on different detection results in different detection ranges so as to carry out different targeted reinforcement treatments.

The deepening blast hole detection method is a method for obtaining geological information by drilling small-aperture shallow holes on a tunnel excavation working face by using an air drill or a rock drilling trolley and the like. The deepened blast hole detection is suitable for advanced geological detection of tunnels under various geological conditions, and is preferably suitable for karst development areas. As shown in fig. 1, the deepened blast hole detection is mainly used for short-term prediction, and the prediction distance may be about 5 m. Thus, by drilling holes to know and release groundwater, the unstable rock formation in front can be positioned with high accuracy.

The geological sketch is to take a field geological object image as an object, and describe the spatial morphology and interrelation of geological objective entities, such as landform landscapes, geological structures, rock minerals and the like by a sketch technique. Often, many characters are used for expressing unclear geological phenomena, but a sketch is expressed clearly, which plays an important role in improving work efficiency and work quality. As shown in fig. 1, geological sketching is mainly used for short-term prediction, and sketched objects may be construction work surfaces or face surfaces. The geological sketch method can analyze the front geology by utilizing the geological excavation condition and is related to the experience of geology workers.

In a specific embodiment, it may be determined whether a short distance forecast is needed based on previous detection results, such as the first detection result and the second detection result. And combining the first detection result and the second detection result to conduct short-distance prediction in a targeted manner. For example, one or more methods of deepening blast hole detection, TIP (TIP position) method, advanced horizontal drilling and geological radar report can be adopted to carry out short-distance prediction, so that the bad geology, the occurrence, position, scale and water-rich condition of faults and the influence on engineering can be accurately judged.

In some embodiments, the detection accuracy of the first level of geologic information is less than the detection accuracy of the second level of geologic information, and the detection accuracy of the second level of geologic information is less than the detection accuracy of the third level of geologic information. Through the gradient type precision detection, accurate and comprehensive detection of geological information and water-rich conditions can be realized. In one embodiment, in order to accurately detect the water-rich condition, the transient electromagnetic method may be used to determine the water-rich position of one or more abnormal segments, and the induced polarization method may be used to determine the three-dimensional image of the water-rich position and the water volume, in combination with the characteristics of different detection strategies. The transient electromagnetic method and the induced polarization method can belong to the same group of detection strategies, and also can respectively belong to different groups of detection strategies. Therefore, the transient electromagnetic method and the induced polarization method are combined to evaluate the water-rich problem in front of the tunnel, the induced polarization method can effectively solve the problem of positioning the water-containing structure in the tunnel construction period, three-dimensional imaging of the water-containing body and water quantity judgment are realized, and the water-exploring capacity in geological forecast is improved.

In some embodiments, one or more preset grouting modes are selected from a set of preset grouting modes for one or more abnormal sections based on the first detection result and the second detection result and optionally the third detection result, and the one or more abnormal sections are grouting reinforced by the one or more preset grouting modes. The grouting process will be described in detail with reference to fig. 2.

Fig. 2 is a schematic flow chart of an overall scheme of reinforcement construction according to an exemplary embodiment of the present invention. In fig. 2, as described above, geological analysis may be performed first based on geological survey data, an abnormal section may be primarily determined, then long-distance detection may be performed on the abnormal section by using TSP method and transient electromagnetic method in long-distance prediction, if the detection result is normal, geological comprehensive determination is performed, if the abnormal section does exist, medium-short distance prediction as described above is performed, and the detection strategy used may be induced polarization method, geological radar method, advanced horizontal drilling method, deepened blasthole (hole) detection method, and the like. In this way, detailed and accurate geological information related to the abnormal section is detected for geological complex judgment.

It should be appreciated that although fig. 2 shows the geological survey data separately, the geological survey data method may also be one of the detection strategies for long distance forecasting and implemented with TSP methods, transient electromagnetic methods in long distance forecasting, as the invention is not limited in this regard.

In some embodiments, after the geological synthesis is determined, a grouting scheme may be determined or selected according to the result obtained by the determination, i.e. one or more preset grouting modes are selected. As shown in fig. 2, the preset grouting mode may be one or more of full-area advanced grouting, peripheral curtain pre-grouting, radial grouting and partial grouting.

Fig. 3 is an engineering drawing of a full face grouting method according to an exemplary embodiment of the present invention, and fig. 4 is a drawing of an orifice arrangement of A-A to D-D sections of the full face grouting method according to fig. 3.

In some embodiments, full face grouting construction may be performed using the example embodiment shown in fig. 3. In some embodiments, overall, full face advanced grouting may employ staged advanced grouting, the sequence may be from outer race to inner race, and the spacer encryption may be performed preferentially. As shown in fig. 3 and 4, the rock mass 3-5m inside the tunnel contour and outside the contour can be reinforced. For example, a drilling machine can be used for forming holes, the diameter of the holes can be 126mm, the depth of the holes can be 2-3 m, orifice pipes can be arranged and fixed after the holes are formed (the diameter of the orifice pipes can be 108mm, grouting holes can be drilled through the orifice pipes, the diameter of the grouting holes can be 90mm, grouting is carried out after the holes are drilled to the depth of the designed holes, the sequence of drilling and grouting can be from an outer ring to an inner ring, and hole isolation encryption is carried out.

With continued reference to fig. 3 and 4, during this full face grouting construction, the port arrangement may be more sparse as the excavation line extends. For example, in the A-A section, the orifices are most densely arranged with minimum spacing between the orifices. In the B-B section, as the excavation line extends, the aperture arrangement is slightly sparse, and the spacing between the apertures becomes large. In the C-C section and the D-D section, the orifice arrangement is further thinned, and the distance between the orifices gradually reaches the maximum of the D-D section.

Fig. 5 is a schematic view of an engineering drawing using a peripheral curtain grouting method according to an exemplary embodiment of the present invention, and fig. 6 is a schematic view of an orifice arrangement according to A-A to D-D section of fig. 5 using the peripheral curtain grouting method.

In some embodiments, perimeter curtain grouting may employ staged progressive grouting as a whole. For example, the outermost ring of holes may be injected first, then the innermost ring of holes, and finally the middle ring of holes, and preferably the spacer-hole encryption grouting. In some embodiments, as shown in fig. 5 and 6, for example, a rock mass within 3-5 m outside the contour line of the tunnel periphery can be reinforced, grouting is performed for a reinforcing length of 30m per cycle, 25m is excavated, and 5m is left as a grouting rock stopping disc of the next cycle. Thus, the outer ring hole (first ring), the inner ring hole (fourth ring) and the middle two rings (second ring and third ring) can be injected first, and the grouting is encrypted by the separation hole.

With continued reference to fig. 5 and 6, during this peripheral curtain grouting construction, the orifice placement may be more sparse as the excavation line extends. For example, in the A-A section, the orifices are most densely arranged with minimum spacing between the orifices. In the B-B section, as the excavation line extends, the aperture arrangement is slightly sparse, and the spacing between the apertures becomes large. In the C-C section and the D-D section, the orifice arrangement is further thinned, and the distance between the orifices gradually reaches the maximum of the D-D section.

Fig. 7 is a schematic cross-sectional layout view of a radial grouting method according to an exemplary embodiment of the present invention. In some embodiments, the radial grouting design reinforcement range can be 5m outside the excavation contour line, and radial grouting is often required under the following conditions, firstly, peripheral rock mass is disturbed and the rock mass strength is influenced under the tunnel excavation unloading effect; secondly, when the deformation of the tunnel soft rock section is large and the tunnel soft rock section is difficult to converge; thirdly, large-area water seepage of the tunnel or water inflow exceeds the design requirement standard, water blocking and emission reduction are achieved through radial grouting. Of course, other cases where radial grouting is required are also possible, and the invention is not limited in this regard. In some embodiments, radial grouting may employ disposable grouting.

Fig. 8 is a schematic diagram of crack water grouting using a partial grouting method according to an exemplary embodiment of the present invention, and fig. 9 is a schematic diagram of planar water grouting using a partial grouting method according to an exemplary embodiment of the present invention. In some embodiments, the reinforcement depth can be 5m to 8m outside the excavation contour line, and the crack water produced by the weak surrounding rock at the local position can be subjected to grouting reinforcement in a grouting mode as shown in fig. 8, wherein grouting holes can be used for grouting near the crack line so as to seal and reinforce the crack. When a water outlet point such as water burst appears, the water burst surface can be treated by adopting a ring type grouting hole shown in fig. 9, and the distance of the grouting hole can be 100mm-150mm or other design distances shown in fig. 9. In some embodiments, localized grouting may employ disposable grouting.

Returning to fig. 2, after determining the grouting scheme by using the above-mentioned suitable grouting reinforcement method or any other suitable reinforcement method, the grouting effect in the grouting process may be detected.

In some embodiments, one or more anomaly segments may be subjected to a water-pressing test during the grouting operation, and when it is determined that the water permeability of the one or more anomaly segments is less than a predetermined threshold, one or more of the anomaly segments may be subjected to re-grouting until the strength of the one or more anomaly segments reaches a design value. Specifically, the water pressure test can be performed after the crack is washed, the pressure can be 80% of the grouting pressure, the maximum pressure is 1MPa, the test can be performed for 20 minutes, the flow is measured and read every 5 minutes, the final flow value is taken as a calculated value, the result is represented by q=q3/L1/P3 by the water permeability (Q is the water permeability (Lu) of the test section, L is the length (m) of the test section, Q3 is the calculated flow (L/min) of the third stage, and P3 is the pressure (MPa) of the test section of the third stage), and when the water yield in the hole is less than 0.15L/min per linear meter, and the physical and mechanical indexes of the rock body are obviously improved, the next round of grouting construction can be performed until the design strength or the target strength is reached.

In some embodiments, the excavated section may be monitored and measured, and the subsequent construction may be guided according to the measurement result. For example, deformation monitoring and hydrologic monitoring may be performed on one or more of the anomaly segments reinforced by grouting.

In one embodiment, the deformation monitoring of the grouting reinforced one or more anomalous sections may include dome subsidence and convergence measurements for the tunnel, the dome subsidence and convergence measurements having a measurement point spacing that is positively correlated with the surrounding rock level of the one or more anomalous sections. Specifically, for example, vault subsidence and convergence measurement can be performed to accurately grasp the displacement change condition of fault surrounding rock in the construction process. In one embodiment, the V-stage surrounding rock measuring point spacing can be adjusted to be 5m in arrangement, and the IV-stage surrounding rock measuring point spacing can be adjusted to be 10m in arrangement, and the special case or the obvious deformation section is properly encrypted in arrangement.

In another embodiment, hydrologically monitoring the one or more reinforced anomaly segments may include determining hydrologic variation parameters for the one or more anomaly segments, and setting an alert threshold, a hazard threshold, and a control threshold based on the hydrologic variation parameters, wherein the alert threshold, the hazard threshold, and the control threshold are each associated with a different remedial action. Specifically, in order to accurately grasp the condition of the laminar flow hydrologic variation in the construction process interruption, for example, monitoring of the water level, the flow velocity, the flow, the water seepage condition in the hole and the like can be implemented. The monitoring may implement three-level management of setting alert, hazard and control thresholds. In a specific embodiment, when approaching the warning monitoring threshold, the construction progress can be slowed down, and the supporting measures can be followed in time; when the dangerous monitoring threshold is close, the supervision can be immediately reported, the reinforced support treatment is carried out first, and emergency remedial measures are reported; when the control monitoring threshold is close, construction can be suspended, constructors and mechanical equipment are evacuated, and related personnel are informed of making construction scheme measures on site.

In one embodiment, with continued reference to FIG. 2, a monitoring outcome feedback regime may be established. For example, regression analysis may be performed on the detection information obtained by the deformation monitoring and the hydrologic monitoring to obtain a deformation regression equation, and based on the deformation regression equation, displacement related information for one or more abnormal segments is obtained, and finally, the displacement related information is subjected to construction site feedback, so that a construction scheme is optimized in time. In other words, regression analysis can be adopted to process data, computer drawing and analysis are used for a large amount of monitoring information, then a deformation regression equation can be calculated to calculate final displacement and master displacement change rules, and monitoring information and monitoring results are fed back to supervision and construction sites in time so as to guide construction and adjust construction schemes and construction parameters in time.

Specific engineering examples for detection of abnormal sections along a tunnel, grouting scheme design and grouting process monitoring according to various embodiments of the present invention are described below.

Yun Mou mountain tunnels pass through two administrative jurisdictions, have complex geological conditions and pass through a plurality of fault fracture zones. Since the fault breaker belt has the risk of water and mud gushing, the following reinforcement scheme is designed with the various embodiments according to the invention:

1. The geological conditions in front of the tunnel are evaluated by adopting comprehensive advanced geological forecast, the position of a fault is determined by a TSP method, a geological radar and advanced drilling, a transient electromagnetic method and a TIP method are combined with each other, the water-rich area and the water content are determined and verified, and an advanced forecast result is submitted so as to be convenient for timely adjusting construction and supporting schemes.

1. TSP method:

(1) Forecasting mileage: YDK15+229-YDK15+379;

(2) Forecast results

YDK15+229-YDK15+278 (length 49 m): the lithology of the section is presumed to have no obvious change compared with the test surface, the rock integrity is poor, the local joint cracks develop, the arch part is easy to fall off and collapse after excavation, the underground water is relatively developed, most points are moist to drop, and the section is recommended to be supported according to class III.

YDK15+278-YDK15+379 segments (length 101 m): the longitudinal wave speed and the transverse wave speed of the surrounding rock are reduced to a certain extent, which indicates that the surrounding rock is softer, the integrity of the rock mass is poor, the underground water is slightly developed, and most of the underground water is in a drop-line flow shape, and the section is recommended to be supported according to class III, and the local area can be supported according to class IV.

(3) Construction advice: during construction, the stability of surrounding rock is required to be paid attention to, the construction method is timely changed according to the surrounding rock condition, engineering geological disasters such as falling blocks and collapse are prevented, meanwhile, the inverted arch and the second lining follow up timely, and engineering and construction safety is ensured.

2. Geological radar:

(1) Forecasting mileage: YDK15+316-YDK15+346.

(2) Forecast results

In the range of 0-4m in front of the face, the radar reflection waveform amplitude is weaker, the cophase axes are generally continuous, and the parts have dislocation, and the middle and high frequency signals are mainly used. The rock mass integrity is general in the presumption range, joint cracks develop, local crushing, interlayer combination and self-stabilization capability are general, underground water develops, and the arch part is easy to fall off in construction. Support according to grade IV is recommended.

In the range of 4-15m in front of the face, the radar reflected wave has strong amplitude, the same phase axis is continuous and takes an arc shape (umbrella shape), and the medium and low frequency signals are mainly used. According to the test radar image, the rock mass in the range can be estimated to have karst, poor integrity, joint crack development, local crushing, poor interlayer combination and self-stabilization capability, and underground water development, and the arch part is easy to fall off and collapse in construction. It is recommended to support in V-class.

In the range of 15-30m in front of the face, radar reflection attenuates fast, amplitude is weak, and phase axis is intermittent, and medium and low frequency signals are mainly used. The rock integrity is generally poor in the presumption range, joint cracks are developed, local fracture is broken, interlayer bonding and self-stabilization capability are generally poor, underground water development is needed to be noted, and arch parts are easy to fall off in construction. Support according to grade IV is recommended.

(3) Construction advice

1) The underground water at the position of the face develops, the underground water is guided and discharged in time in site construction, and the proposal of adding the advanced exploratory hole is that the underground water in surrounding rock is discharged in time.

2) The geological survey shows that the permeability coefficient of the isthmus is larger, the abnormal low resistance characteristic is generated, the conditions of cavity generation are provided, and the construction should be closely paid attention.

3. Advanced drilling

(1) The position of the face of the current construction is YDK15+316. 4 drill holes are constructed, and the method mainly detects hidden disaster conditions in the excavation range of 50m in front of the tunnel;

(2) Analysis of results: the water is gushed from 4 holes, especially 1, 3, 4# Kong Mankong water, 1, 3# Kong Shuiliang clear and slightly turbid 4# hole water; the water in the 2# holes is only thick with the thumb and the water color is yellow mud. Because the holes are close in position, water flows together, and the water inflow of a single hole cannot be measured.

(3) Construction advice:

1) At least 5 deepened blastholes are required to be constructed in each cycle of excavation, and the deepened blastholes are at least 2m higher than the normal blastholes and are respectively positioned at the left middle, the right upper part, the middle, the right upper part and the right lower part of the face;

2) The face is positioned between the inclined axis of the back of the nose isthmus and the F3 reverse fault, water burst and crack observation of the face are enhanced, and karst disaster risks are analyzed by combining with the deepening holes of the blastholes.

4. Transient electromagnetic method

(1) Detection site: YDK15+316 face

(2) The effective detection range of the transient electromagnetic method is 10-100m (the range of 0-10m is the detection blind zone)

The resistivity of the front 10-30m of the palm face is low as a whole, and the underground water in the area is estimated to develop very much, so that the water is discharged in a surge shape;

the resistivity of the front part of the palm face is 30-60m, the whole lower resistivity deduces that the groundwater in the area is very developed, the joint fracture water is the main part, and the groundwater presents linear flowing water;

the resistivity of 60-100m in front of the face is improved, the general development of the underground of the area is deduced, and the face is moist and dribbled;

(3) Construction advice

1) The underground water in front of the face is very developed, the water outlet form is mainly in a spray shape, the water pressure is high, the arch part is easy to fall off and collapse after excavation, the water draining hole is recommended to be drilled firstly, and the next excavation operation is carried out after the pressure of the water draining hole is reduced.

2) It is suggested that the front groundwater pressure is ascertained by adopting various modes such as a exploratory hole, and the advanced exploratory hole can play a certain role in pressure relief of high-pressure groundwater to a certain extent.

5. Induced polarization method (TIP method)

(1) Forecasting mileage: YDK15+316-YDK15+346.

(2) Forecast results: the resistivity value is low overall, an obvious low-resistance area exists 5m behind the front excavation, and the abnormal area is water drop. And deducing that the section of stratum is strong in water enrichment according to the distribution range and the abnormal size of the resistivity abnormal region, and that strand-like running water possibly appears at the development position of the partial fracture of the face during excavation.

(3) Construction advice

1) The fracture is developed, and the surrounding rock collapse phenomenon is possibly generated due to the weakening effect of the groundwater on the structural surface, so that the monitoring work is enhanced and the protection is well carried out.

2) In the process of excavation, the change of surrounding rock and underground water on site is required to be noted, the water quantity can be increased from the front 10m of the face (especially the right side of the face), meanwhile, the construction monitoring is enhanced, grouting blocking and timely drainage are carried out, and the protection work is well carried out.

2. And (3) according to the advanced forecasting result, timely adjusting the construction and support scheme, adopting a proper grouting and water shutoff mode, and selecting curtain grouting construction according to the advanced forecasting result in a certain river water reservoir section. And drawing drilling positions on the face according to grouting design, and marking numbers. And (3) drilling by using a drilling machine, and starting to drill grouting holes after the position and the direction of the orifice pipe are checked accurately.

3. Deformation monitoring and hydrologic monitoring are needed in the construction of crossing faults.

1. Deformation monitoring: grasping the displacement change condition of fault surrounding rock in the construction process, and monitoring convergence and sinking

(1) Instrument: tunnel peripheral convergence gauge, precise level gauge, total station and digital camera

2. Hydrologic monitoring: monitoring water level, plastic flow, flow rate, water seepage in hole and the like

(1) Instrument: levelling staff and flow velocity meter

Through the steps, the targeted grouting water treatment reinforcement is successfully realized. Not only improves the construction efficiency, but also reduces the construction cost, ensures that no safety accident occurs in the construction process, smoothly passes through the fault fracture zone, effectively reduces the risk caused by geological disasters occurring in the construction stage,

the result shows that the targeted grouting reinforcement technology is very effective on the basis of fully knowing the water damage condition and the grouting condition permission by utilizing comprehensive geological prediction, and can play a role in water shutoff and reinforcement.

In summary, according to the embodiments of the present invention, whether a fault exists, the position, the nature, the scale and the water content of the fault are gradually determined through multi-stage advanced detection, so that resource waste caused by excessive reinforcement and safety accidents caused by insufficient reinforcement are effectively avoided; in the tunnel excavation process, the mechanical properties and the hydraulic properties of the rock mass can be changed, and according to the scheme provided by the invention, the geological conditions in front of the construction work face can be dynamically detected, and the construction scheme can be timely adjusted; the multi-stage advanced prediction gradually increases the detection precision along with the detection range from far to near, and can detect more kinds of target objects, thereby being beneficial to dynamically adjusting the reinforcement scheme and taking targeted reinforcement measures; by means of advanced prediction, the grouting water shutoff scheme is directionally implemented, so that quick construction is facilitated, and cost is saved; the transient electromagnetic method and the induced polarization method (TIP method) are combined to detect the front water distribution characteristics, the water containing position is firstly judged preliminarily through the transient electromagnetic method, and then the induced polarization method is combined to effectively solve the problem of positioning of the water containing structure in the tunnel construction period, realize three-dimensional imaging of the water containing body and water quantity judgment, and improve the water detecting capacity in geological forecast.

While several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of the invention. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination.

The foregoing description of embodiments of the invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the technical improvements in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (7)

1. A reinforced construction method for traversing a water-rich fault fractured zone tunnel, the method comprising:

determining a first detection result by using a first group of detection strategies within a first detection range of a first detection distance from a construction working surface of the tunnel, wherein the first detection result indicates first-level geological information associated with one or more abnormal sections in the first detection range, and one or more abnormal sections comprise the water-rich fault fracture zone, and the first group of detection strategies comprises a TSP method and a transient electromagnetic method;

Detecting one or more of the anomaly segments within a second detection range of a second detection distance from a work surface of the tunnel using a second set of detection strategies to obtain a second detection result, wherein the second detection result is indicative of second-level geological information associated with one or more of the anomaly segments, and wherein the second detection distance is less than the first detection distance, the second set of detection strategies including a geological radar method, an induced polarization method, and a look-ahead horizontal drilling method, and the transient electromagnetic method and the induced polarization method in combination detect water-containing distribution characteristics of one or more of the anomaly segments, wherein the transient electromagnetic method is used to initially determine a water-containing location and the induced polarization method is used to locate a water-containing formation, the first-level geological information having a detection information accuracy, a detection object, and a detection range that are different from the second-level geological information, and the detection accuracy of the first-level geological information is less than the detection accuracy of the second-level geological information;

based on the first detection result and the second detection result, one or more preset grouting modes are selected in a group of preset grouting modes aiming at one or more abnormal sections in a targeting manner, wherein one or more preset grouting modes can be dynamically adjusted; and

Grouting and reinforcing one or more abnormal sections by using one or more preset grouting modes;

wherein the method further comprises:

determining whether to detect within a third detection range from a construction working face of the tunnel by a third detection distance based on the first detection result and the second detection result, wherein the third detection distance is smaller than the second detection distance;

detecting one or more of the anomalous segments with a third set of detection strategies when it is determined that detection is to be performed within the third detection range to obtain a third detection result, wherein at least one strategy of the third set of detection strategies is different from a strategy of the second set of detection strategies and the third set of detection strategies includes one or more of deepening borehole detection, induced polarization, advanced horizontal drilling, geological radar, geological sketching, wherein the third detection result is indicative of third-level geological information associated with one or more of the anomalous segments, the third-level geological information having a detection accuracy greater than a detection accuracy of the second-level geological information; and

and selecting one or more preset grouting modes based on the first detection result, the second detection result and the third detection result.

2. The method according to claim 1, wherein the method further comprises:

performing deformation monitoring and hydrologic monitoring on one or more abnormal sections reinforced by grouting;

wherein said deformation monitoring of said grouting reinforced one or more of said anomaly segments comprises dome subsidence and convergence measurements for said tunnel, said dome subsidence and convergence measurements having a measurement point spacing that is positively correlated to a surrounding rock level of one or more of said anomaly segments; and

wherein the hydrographic monitoring of the grouting reinforced one or more of the anomaly segments comprises determining a hydrographic variation parameter for one or more of the anomaly segments, and setting an alert threshold, a hazard threshold, and a control threshold based on the hydrographic variation parameter, wherein the alert threshold, the hazard threshold, and the control threshold are each associated with a different remedial action.

3. The method according to claim 1, wherein the method further comprises:

carrying out a pressurized water test on one or more abnormal sections in the grouting construction process; and

and when the water permeability of one or more abnormal sections is determined to be smaller than a preset threshold value, re-grouting the one or more abnormal sections until the strength of the one or more abnormal sections reaches a design value.

4. The method of claim 1, wherein the first detection distance is no less than 100 meters, the second detection distance is no greater than 80 meters, and the third detection distance is no greater than 40 meters.

5. The method according to claim 1, wherein the method further comprises:

judging the water-rich position of one or more abnormal sections by adopting the transient electromagnetic method; and

and determining the three-dimensional image of the water-rich position and the water volume by using the induced polarization method.

6. The method of any one of claims 1 to 5, wherein the set of pre-set grouting modes includes one or more of full face advanced grouting, perimeter curtain pre-grouting, radial grouting, partial grouting; the full-section advanced grouting is carried out from the outer ring to the inner ring in a sectional advancing manner and hole separation encryption is carried out; the peripheral curtain pre-grouting adopts forward type sectional grouting, and sequentially comprises the steps of firstly grouting an outer ring hole, then grouting an inner ring hole, finally grouting an intermediate ring hole, and performing hole isolation encryption; the radial grouting and the local grouting adopt disposable grouting.

7. The method according to claim 2, wherein the method further comprises:

Carrying out regression analysis on the detection information obtained by the deformation monitoring and the hydrologic monitoring to obtain a deformation regression equation;

acquiring displacement related information for one or more abnormal segments based on the deformation regression equation; and

and feeding back the displacement related information to a construction site, and optimizing a construction scheme in time.

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