The contamination of heavy metals in soil constitutes a serious environmental risk. This paper discusses the concept of bioavailability/accessibility of heavy metals and the affecting factors, presents the progress in the study of experimental methods of selective extraction, and indicates the data application and research direction. The speciation and bioavailability of heavy metals in soil depend on elemental geochemical behavior, source of contaminants, physico-chemical condition of soil, rhizosphere enhancement and some other factors. Single and sequential selective extraction is the effective and operational methods to reflect the speciation and bioavailability of heavy metals in soil. As hand-to-mouth activity is the important pathway for soil Pb exposure to children, in vitro digestion methods have been developed to evaluate the bioaccessibility of heavy metals. Bioavailability and bioaccessibility of soil contaminants seem to be the key parameters for risk assessment. The results of selective extraction also provide the basis for contaminated soil remediation.

Airborne geophysical survey is a kind of special geophysical exploration technology based on various types of aircrafts equipped with airborne geophysical instruments,alying along the planned route. The aero-geophysical exploration result is not only affected by geophysical equipment performance but also controlled by the flight platform used and the flying control. Therefore, a reasonable choice and use of the aircraft is the primary task to carry out aero-geophysical survey work. Based on reviewing the development of the domestic aero-geophysical survey, the authors divide the main aero-geophysical aircrafts into four types, i.e., fixed-wing aircrafts, helicopters, unmanned aerial vehicles and other vehicles. The advantages and disadvantages of each type of aero-geophysical aircrafts are analyzed in this paper. Furthermore, the main development direction of the aero-geophysical survey and the flying platform are forecasted from the needs of the geological exploration.

Based on calculation of geochemical characteristic parameters, geochemical anomaly characteristic values and integrated geochemical anomaly indexes, the authors obtained six geochemical parameters: rejection ratio, variation coefficient, concentration ratio, enrichment coefficient, mineralization coefficient, single element geochemical anomaly index and composite geochemical anomaly index, which can be used to conduct quantitative evaluation of geochemical anomalies.

The Luohe-Xiaobaozhuang iron ore district is located in Lujiang County, Anhui Province. The newly discovered Xiaobaozhuang ore deposit is buried at the depth of 1 350~1 800 m, 800~1 000 m under the Luohe main orebody. Before drilling engineering, it is necessary to separate Luohe magnetic anomaly in the upper part and Xiaobaozhuang magnetic anomaly in the lower part. Through the wavelet multi-scale transform, Xiaobaozhuang magnetic anomaly at the depth was separated and extracted perfectly. The large-size orebody predicted by six-step detailed anomaly was used to guide drilling exploration. The wavelet multi-scale transform can decompose gravity and magnetic anomalies in space at different scales and can effectively separate vertical superposition gravity-magnetic anomalies. The results achieved by the authors can be applied to exploration of the same type of iron deposits.

According to the obvious differences of resistivity between major rocks and ore bodies, the magnetotellic method was employed in the Yanjiagou gold deposit of Huailai County, Hebei Province. In this paper, the authors processed and analyzed the data collected in the study area by some precision instruments, and constructed the resistivity gradient profile model. On such a basis, some low-resistivity zones were detected, which accorded well with the result of drilling exploration and high precision magnetic survey. Some anomalous belts of low resistivity were found in the surveyed area, which are distributed at the depth of or near western site 11, southern site 54 and eastern site 21 and are considered to be places favorable for minerization. The study results provide useful geophysical information for prognosis of concealed orebodies in covered areas.

Geophysical and geochemical exploration in Taishanmiao area of Xixiang district within southern Shaanxi is characterized by low work extent, single exploration method and very insufficient anomaly information. In order to investigate the distribution, extensional boundary and deep variation of the magnetite deposit in the basic rock mass, the author adopted ground high-precision magnetic method and utilized such methods as upward continuation and 2.5D human-computer interactive inversion in conjunction with 1:25 000 stream sediment survey results and geological characteristics to make interpretation and deduction of anomalies. Through careful processing of data obtained from ground high-precision magnetic survey, the author delineated the range of magnetic anomaly, determined the distribution and spatial characteristics of magnetite deposit in the basic rock mass, thus providing the verifiable target for further deployment of geological exploration work.

In gold deposits, Au and Bi are often associated with each other. Around the gold orebody, there exists obvious Bi anomaly, which can serve as an important indicator element. The authors investigated the relationship between Bi and Au content in different rocks within the Linglong gold mine, comparatively studied the correlation of these two elements in the bedrock geochemical profile, and analyzed Bi and Au content in main ore minerals by means of electron microprobe analysis. Some conclusions have been reached: Bi values are remarkably different in different kinds of rocks, Bi values in the orebody are by far higher than its values in the wall rock, Bi and Au show power function positive correlation in the ore district, Bi primary halo is of large size and high contrast, and both Bi and Au exist as independent minerals. Geochemical prospecting in the Linglong gold mine shows that Bi is of high content, has fairly good positive correlation with Au and thus can serve as one of the best indicator elements.

The Tangjiaping granite-porphyry type molybdenum deposit in Shangcheng County of Henan Province is a typical granite-porphyry type molybdenum deposit with ultra-acid, alkali-rich and K-high characteristics. Molybdenum mineralization is closely related to potash alteration and silicification. Relatively strong Mo anomaly is consistent with the extent of the molybdenum deposit, and ΔT exhibits relative negative magnetic anomaly. Based on geological, geophysical and geochemical characteristics, the authors established an integrated ore-prospecting model for the granite porphyry type molybdenum deposit and, on such a basis, found a semi-concealed large molybdenum deposit and objectively evaluated quite a few Mo anomalies in China, thus achieving fairly good application results.

The study area lies in the Dong Ujimqin Banner iron polymetallic ore belt. Quite a few 1:50 000 geochemical anomalies are distributed in this area and characterized by predominant medium-low temperature elements, large anomaly sizes, large quantities, and high peak values. The Duolungou mining area has a 1:50 000 composite geochemical anomaly of Ag, Pb and Zn. The 1:10 000 soil survey shows that the anomaly has element concentration zoning and a good consistency with the concentration center, and can be decomposed into several secondary anomalies characterized by predominant Ag. Several alteration belts are developed in secondary anomalies, in which there exist polymetallic orebodies dominated by silver. The preliminary trenching demonstrates that the quantity of silver in a single silver sample is up to 1 332×10^-6, associated with Pb-Ag orebodies. The anomalies might result from the polymetallic orebodies dominated by Ag, suggesting that this area has good prospecting potential and is expected to form another important silver polymetallic ore belt in Inner Mongolia.

Gas hydrate is a new energy, and many countries in the world are doing research on gas hydrate. Southeast Hainan is the most important objective place on the northern slope of the South China Sea. Therefore, the research on two-dimensional seismic data in Southeast Hainan for seismic reflection characteristics of gas hydrate formation is helpful for further clarifying the relationship between distribution of gas hydrate and seismic reflection characteristics. The authors have obtained more knowledge on seismic reflection characteristics of gas hydrates in Southeast Hainan, such as bottom simulating reflector (BSR), BSR strong reflectors above the speed anomaly, BSR near amplitude blanking, BSR polarity reversal. The results achieved by the authors are of important significance for the study of BSR-containing characteristics of the whole study area.

According to the characteristics of oil and gas reservoirs and the basic principles of the non-seismic geophysical and geochemical exploration methods, the authors analyzed the function of the non-seismic geophysical and geochemical indexes. The result shows the close corresponding relationship between the indicators of the non-seismic geophysical and geochemical exploration methods and the beneficial hydrocarbon zones which are located in oil and gas zones of the Ordos Basin. An optimized combination of the non-seismic geophysical and geochemical exploration methods in the prospecting for oil in the Ordos Basin is put forward in this paper. The results achieved by the authors will play a guiding role in the further oil prospecting work in the Ordos Basin.

In recent years, a large number of dolomite lithologic gas reservoirs have been found in the middle part of Ordovician strata in the Shanbei loess tableland. Nevertheless, the surface conditions of this area are complex, which leads to a poor seismic data imaging accuracy, and the main reservoir Mawu5 Formation of Ordovician is characterized by extensive distribution,thin reservoir,strong heterogeneity and drastic lateral variation in physical properties, which results in more difficulties in seismic prediction. With the 3D high-fidelity seismic data of 600 km² collected in the Shanbei loess tableland in recent years, technologies of FFP analysis and function formula between the elastic parameters fitted by drilled wells were applied innovatively based on an analysis of rock physical sensitive factors and the strengthening of pre-stack inversion. The dolomite probability, gas probability, porosity and gas saturation of Ma55 Formation in the project was calculated. The favorable gas area in the dolomite reservoir of Ma55 in the Su203 well district was described clearly, and then the favorable drilling targets were evaluated and obtained, thus achieving good results.

Chishanhu area is located in Jurong City of Jiangsu Province. Jurong belongs to the southern Jiangsu region of Yangtze block and has poor hydrogeological conditions. In combination with gravity, electrical sounding and MT, geological and drilling data, the authors chose resistivity inversion profile of CSAMT and microtremor measurement to explore lithology and depth of the thermal reservoir and location of the fault. Based on geothermal and hydrogeological conditions, the authors confirmed the geothermal well site and then successfully revealed a hot spring with water output of 500 m³/day and temperature 55℃ through actual drilling.

The Jiaojia faulted zone is one of the major ore-forming faults in the northwest Shandong gold ore concentration area. As it is seriously covered by Quaternary sediments in the south, years of investigation is unsuccessful. In this study, various geophysical methods such as high-precision magnetic survey, apparent resistivity united profile, CSAMT and SIP were used in combination with metallogenic geological conditions of the study area to tentatively investigate the southward extension of the Jiaojia faulted zone. As a result, the distribution of concealed faults in the southward extension part of the Jiaojia faulted zone was deduced, which provides ore-prospecting orientation for the next step of gold exploration.

In the Altay high latitude glacial till covering area, an analysis of rock magnetic data shows that magnetic properties of rocks are different from each other conspicuously. The magnetic anomaly identification marks have been established preliminarily. The magnetic field can be divided into three districts: Ⅰ-1 high stability zone corresponding to biotite granite, and Ⅰ-2 highly jumping magnetic field zone reflecting the distribution of Silurian hypometamorphic rocks; Ⅱ medium stability magnetic field zone corresponding to two-mica granite; Ⅲ low magnetic field zone representing the reflection of Sinian-Cambrian weak to non-magnetic epimetamorphic rocks. Eight NW-and NE-trending concealed faulted structures were determined through deduction. The results achieved by the author provide geophysical basis for the construction of the structural framework of this area. The ground high-precision magnetic survey is effective in supplementary geological mapping of the glacial till covering area and plays a guiding role in practical geological mapping.

It is difficult to achieve the ideal square pulse current especially with high inductor load, low loop resistance and low input voltage; therefore, time domain airborne electromagnetic systems such as GEOTEM mostly adopt the half sine wave transmitting circuit to realize the large magnetic moment of emission. This paper describes the design of a novel quasi-resonant modified pulse emission circuit. The modified waveform current generated by this special transmitter with the short edge times is somewhat similar to square waveform, the ideal wave form of broad band transient. On such a basis, a set of fix-wing airborne electromagnetic pulse transmitting system has been developed recently, whose pulse current reaches 650 A and peak moment is up to 500 000 Am².

This paper has analyzed the calculation precision of G-S transformation and Hankel transformation, when n = 12 or 16, G-S transform applicability is wide and can assure accuracy, and the relative accuracy of Hankel transform is up to 10^-6 orders. Based on time-domain airborne electromagnetic method in time domain and dipole-dipole device 1-D forward modeling algorithm,, the authors analyzed the precision of response to airborne electromagnetic wave when different parameters were selected. The results show that the G-S transformation value of an influence on calculation accuracy is considerable, and selection of parameters of Hankel transformation filtering has small effects on calculation accuracy.

In the exploration of deep concealed orebodies, the large distance between the iron orebody and the observation surface may produce only one broad magnetic anomaly which can't distinguish ore-related anomalies and background-induced anomalies. The application of upward continuation and derivatives fails to obtain satisfactory results. During the case study in Qinghai Province using downward continuation, the authors obtained the fine anomalies based on the downward continued field with a distance of 30 times that of the grid interval. The comparison of the downward continued field with many magnetite-bearing and non-magnetite-bearing drill holes revealed a clearer relationship between the magnetic anomalies and the ore-intersecting drill holes. It is also shown that all of the non-magnetite-bearing drill holes are located outside the downward continued field. Since it is possible to apply the stable downward continuation at present, the authors hold that the downward continuation of the anomaly with a large buried depth is useful in distinguishing superimposed anomalies and detecting the anomaly's location, thus providing evidence for planning the mining operations. The exploration accuracy is also discussed in this paper.

In view of the stratigraphic characteristics of the pediment hilly area of the Luliang Mountains, the authors conducted a selective study of the CSAMT data collection frequency, carried out comparative test and application based on the results of groundwater and geothermal exploration and, as a result, achieved satisfactory geological effects. Tests show that, for the relatively deeply buried but not very thick strata, the encryption of the data acquisition frequency density can improve the resolution capability and detect all significant small anomalies; Especially in the case that the exploration data are deep groundwater aquifers and thin layers, the application of high-density frequency to conducting data acquisition can increase the quantity of investigated information and achieve good geological results.

Tensor measurement and scalar measurement of the CSAMT method were conducted in two known iron ore districts of Anhui Province, and a comparison of the application results was made along the known geological exploration section. The results of the test show that, under the condition of 1-D layered electrical property structure, the ore-prospecting result of the tensor measurement is close to that of the scalar measurement, whereas under the condition of complex electrical property structure, the ore-prospecting result of the tensor measurement is better than that of the scalar measurement. Some problems which require further investigation in the tensor measurement of the CSAMT method are also discussed in this paper.

Based on the application of DGPS in GT-1A airborne gravity measurement system, the authors discussed the selection and precision of GPS stations, and analyzed a variety of calculated free air anomaly results in detail. The final results indicate that the different values of GPS basic station position induces the horizontal error of free air anomaly on survey lines, and the results on the same survey line can almost reach the same precision after horizontal adjustments. In addition, the distances between GPS basic stations and rover stations have impacts on the locally detailed amplitudes of free air anomaly. After horizontal adjustments, the internal accord accuracy on the same survey line can reach almost 0.3.

The widespread net-shaped fracture reservoirs have good reservoir capacity. The dual laterolog can recognize fractures effectively. The dual laterolog logging response within the net-shaped fracture reservoir was simulated through the 3-D finite element method, with emphasis placed on the influence of logging response such as fluid resistivity, bedrock resistivity and fracture dip. The results show that the apparent resistivity increases with the increasing fluid resistivity in the fracture, but the rate is pretty small. The apparent resistivity increases with the increasing bedrock resistivity, but this kind of influence will decrease when the bedrock resistivity is very small. The net-shaped fractures formed by the low angle fractures often hinder current strongly. The conclusions above can provide theoretical reference for the horizontal well bore logging evaluation with the net-shaped fracture reservoir.

In this paper, the magnetotelluric two-dimensional finite element forward modeling program was used to simulate a two-floor earth geoelectric model of low resistance static shift and study the principle of static shift and its impact. The wavelet transform was also used to suppress the static shift. In contrast to other conventional spatial filtering methods, the method adopted by the authros can obtain a better suppression result, thus confirming the feasibility and effectiveness of applying the wavelet transform method to suppressing the static shift. Finally, the authors used the wavelet transform method to analyze measured EH-4 data in a work area, identified and determined the static shift from the mathematical model. It is shown that wavelet transform method for data processing can attain a good suppression. This method can retain the original layered structure information and local anomalies caused by the geological anomaly body while suppressing the static shift.

The complex piedmont zone with good reservoir conditions is an important field of oil and gas exploration. However, the seismic data have a low signal-to-noise ratio and poor imaging accuracy because of the complex surface and near-surface and subsurface structure. Based on the shooting characteristics which exist in the gravel area of piedmont zone the authors consider that we could conduct points design with the aid of Google Earth platform during the process of selecting piedmont shooting points. The principle of selecting low areas instead of high areas, gravels instead of rocks and flattened places instead of steep places should be adopted during the selection of shooting points. Tomographic inversion technique goes for the investigation of the piedmont surface layer. The well depth design should be shot in the areas with high speed, strong shooting energy and high excitation frequency. The data acquisition of ZD district indicates that the shooting way of the piedmont gravel area adopted in this paper can improve the quality of seismic data.

Based on advanced theory of TGP (Tunnel Geological Prediction) and actual engineering data, the authors applied information logic method to analyzing TGP 2D and 3D geological prediction results and mainly compared the similarities and differences in the aspects of the geological structure position, scale, surrounding rock classification and attutude. The results show that, if the surrounding rocks in front of the tunnel have no obvious difference in lithology, 2D and 3D geological prediction results are essentially the same. When the geological structures and tunnel are obliquely crossed, 2D and 3D are similar in the prediction results of tectonic attitude; however, 2D is advantageous in the surrounding rock classification prediction, and 3D is advantageous in the size and location prediction. Where the geological structure does not intersect with the tunnel side wall which is near the hole line excitation, 2D and 3D geological prediction results are substantially different, and 3D geological prediction results are better than 2D prediction results.

The study of the electric anisotropy properties of strata can delineate oil and gas reservoirs in the strata and the deep linear structure related to geodynamic process and earthquake prediction. On the basis of magnetotelluric response formula in N-layer tilted electric anisotropic media obtained by the authors and under the condition of different electric anisotropy coefficients, dip angles of strata and thicknesses of tilted beds, the authors conducted forward calculation of the model for electric anisotropic tilted strata. The results show that, when any one of the three variables (electrical anisotropy coefficient, dip angle of strata, and depth of strata) is changed, the shape of the apparent resistivity curve remains basically unchanged, but the amplitude value of the apparent resistivity curve varies considerably, that the apparent resistivity curve is most sensitive to the change of the dip angle parameter of strata, and that the increase of the electric anisotropy coefficient can clearly demonstrate the resistivity anomaly of the thin layer. The results achieved by the authors will be helpful to electric anisotropic media magnetotelluric inversion and applied research in future.

According to the investigation of heavy metal content in topsoil and deep soil in the east of Qinghai, the authors used National Standard ( GB15618-1995) as the evaluation standard. The status of heavy metals in the soil was evaluated, and the situation of heavy metal pollution in Ganhetan was discussed by combining single soil samples, plant samples, water samples and geochemical sections. Two heavy metals (Cd, Hg) were selected to compare the situation of their pollution in different periods. The results indicate that the heavy metal pollution in eastern Qinghai is not serious, but some heavy metals such as Zn, Cd, Pb in Ganhetan have formed obvious circular pollution, and the pollution has reached deep soil. Agricultural development is not suitable in this area. It is found that the pollution of some heavy metals such as Cd has aggravated, whereas pollution of some heavy metals like Hg has been reduced.

Based on a study of soil environment contamination situation of the Dongying oil-gas exploitation area, the authors have found some regularities: in soil near the well mouth, Cr, Pb and Zn values are relatively high, which, however, tend to decrease away from the well mouth; Cd values are high at the well mouth, and gradually decrease and become stable in soil on both sides of the well mouth; Cr and Zn values are remarkably affected by the pollution of the falling oil, with the influence range within 1 m; Cu, Ni, Pb and As values do not show obvious change with the depth, and only slightly increase at the depths of 80 cm and 1 m; in soil near most wells, the maximum values of saturated hydrocarbon, aromatics, hydrocarbon and asphalt exist at the well mouths, which is consistent with the phenomenon that the falling oil is likely concentrated at the well mouth; the hydrocarbon content tends to decrease gradually with the elapse of the time, which suggests that the longer the exploitation time, the more serious the hydrocarbon pollution.

Based on geochemical investigation of soil in the study area, the authors studied characteristics of selenium distribution, sources and physical-chemical properties of soil in the Beibu Gulf coastal economic zone of Guangxi. The results show that the total se-lenium content in surface soil is from 0.06×10^-6 to 0.90×10^-6, with the average value of 0.44×10^-6. The total selenium content in deep soil is from 0.07×10^-6 to 0.92×10^-6, with the average value of 0.44×10^-6. The total selenium content in the surface soil to a certain extent has inherited the selenium from the parent materials. The correlation analysis indicates that the total selenium content in soil has a significant positive correlation with carbon, organic carbon, aluminum oxide and total iron oxide, indicating that organic carbon, iron and manganese oxides in the soil and the weathering and leaching extent play important roles in the geochemical behaviors of selenium. The ecological quality of the study area is excellent with the potential of developing selenium-rich agricultural products.

Dipole method can be used to detect the leakage on the impermeable membrane. The thickness of the medium on the impermeable membrane and the distance from the detection point to the membrane will influence the sensitivity of dipole detection. Based on the principle of high voltage DC leakage detection method, the authors analyzed the influence of medium's thickness on the detection. The results show that it is difficult to detect the leakage by moving the dipole on the medium surface when the thickness of the medium increases, but if the dipole can approximate the membrane, the dipole can detect the obvious potential abnormalities when it is approaching the leak.

Absorptive attenuation has always been one of the reasons for the limited resolution of the seismic data.The mechanism of the absorption in strata,the evaluation of the attenuation quantity and the compensation of the high frequency components are essential in the seismic resolution improvement.Based on ARX model,the authors simulated the reversion of the absorption process in strata by establishing a numerical model with system identification technology.The low frequency data (the surface seismic data) and the high frequency data (the well log data or the cross-well seismic data) are respectively set as the input and the output of the model,and then the structure parameters of the model can be obtained.The model in this paper can establish an interconnection between the conventional seismic data and the well log data,the cross-well data or the VSP data.It is shown by processing the practical data that the main frequency can be increased by 10~15 Hz,and the frequency band width can be expanded by 8~10 Hz.

In order to study the mechanism and propagation of Rayleigh surface wave in biphasic media and promote the development of data-processing method of Rayleigh surface wave, the authors applied finite difference method with staggered grids to simulate the 2D isotropic elastic media based on the elastic wave equation, and made a comparison between the analytical and numerical solutions. On such a basis, the PML absorbing boundary condition and improved image method can be applied to the two-phase medium wave equation to simulate the typical media model including horizontal layer and undulating interface, analyze the full wave information including the Rayleigh surface wave and body wave, and make a stability analysis. The results show that, on the basis of the comparison between the numerical solution and the analytical solution of the elastic media within the acceptable range of the error, the study of biphasic medium is feasible. The slight improvement of the image method can be applied to biphasic media to deal with free boundary condition problem of the Rayleigh surface wave effectively. The detailed analysis of the full wave field information of biphasic media including the Rayleigh surface wave and body wave shows that it has played a guiding role in the seismic exploration on the basis of biphasic media.

Based on the platform of ObjectARX in AutoCAD 2002, the authors used Microsoft Visual C++ 6.0 to exploit a plug-in for generating the magnet profile and transplanting it to AutoCAD 2004 with the help of Microsoft Visual Studio.net. The plug-in only needs the preprocessing of magnet data and files containing corner coordinates of the magnet profile, and selects map scales, vertical axis ratio, map titles and point distance simply; that is, on the basis of presetting, it can directly create profiles that have such related elements as titles, scales, frames, responsible tables, and legends. The generated profile is characterized by elegance and easy operation and can thus reduce the burden of illustrators effectively.

In order to realize the high precision surveying in regional gravity survey as well as the transformation of different systems of coordinates, this paper describes a method for refining the local quasi-geoid and develops software to realize conversion from the GPS geodetic height to normal height. The conversion precision is ±5.57 cm by the external check using 26 benchmarks, which can completely meet the requirements of elevation precision in gravity survey.

The third-generation coherence algorithm,C3,is robust to suppress noise and posseses high resolution.However,the process of computing eigenvalues of the covariance matrix in C3 is time-consuming.To avoid computing all eigenvalues,this paper proposes a fast convergence algorithm based an eigenvalue estimation of real symmetric matrices to calculate the dominant eigenvalue.To control the precision of the algorithm,this paper presents an error evaluation formula.By adding traces along the boundary of the seismic data volume,we avoid judging whether the spatial window oversteps the boundary when recursion strategy is applied in a horizontal direction.The application to real data shows that the efficiency of C3 is improved by approxinately 3 times.

Airborne geophysical survey is conducted along the route programming with the application of GPS. Line data constitute the foundation of airborne geophysical data processing and interpretation and are distinguished by the line indexes. The development of unattended operation without human intervention might result in the loss of line indexes. Based on an analysis of the operating characteristics of the aero-geophysical survey, the authors put forward the unattended line index editing design scheme, and developed the line index automatic editing software which uses the plug-in technology on the GeoProbe geophysical software platform, thus improving the work efficiency of airborne geophysical field.

The grouting reinforcement of the coal seam floor and the construction of aquifers are effective methods in preventing and controlling of karstic water disaster in the coal seam floor above the confined aquifer during safe mining.In order to evaluate the effect of grouting reinforcement in the coal seam floor, the authors set the Ⅱ615 working face of the Hengyuan coal mine in northern Anhui Province as the study object and selected normal regions as well as abnormal regions.In addition,wave velocity detection was conducted for floor rocks before and after grouting in each region respectively by logging with seismic wave in drill holes.The results show that there is a considerable difference in wave velocity between the normal and abnormal regions before grouting,and the wave velocities in the two regions are basically the same after grouting.The wave velocity of floor sandstone strata rises obviously after grouting and it is 1.2 times the wave velocity before grouting.However,the wave velocities of marine mudstone change only insignificantly before and after grouting, which is in accordance with the completeness of rock core and non-guide rise exposed by drill holes.All this fully indicates that grouting could play a good role in the reinforcement of crack rocks.

The underground pipeline detection with small intervals and non metal are two major problems in current pipeline detection, plus the complicated layered medium and the influence of interference factors, thus increases the difficulty of the pipeline detection,and it is difficult to judge target abnormal bodies on radar section. In order to locate the target line and improve interpretation accuracy, in view of the two big detection problems and interference factors, we uses GprMax software and Matlab language to simulate pipeline models under complicated layer condition. The simulation results indicates that the pipeline lateral resolution of 250 MHz antenna frequency is 50 cm in the case of 1m depth. Radar reflection wave image of mental and non mental are different.Therefore,based on these information to judge the filling material and the size of pipeline. The results of simulation can play a substantive role in actual complicated underground pipelines detection.