1 Project Overview

The Beijing-Hangzhou Grand Canal Xie Taiwan second-tier ship lock project is to use World Bank loans to invest in our province the construction of key transportation projects, locks Jiawang District, Xuzhou City is located in Wu Zhen, from the urban area of about 20km, in the Jiangsu section of the Beijing-Hangzhou Grand Canal waterway Xie Taiwan western North line lock side.

Taiwan second-tier ship lock solution in parallel with the line lock arrangement, the two gate centerline distance 90m, lock the fundamental scale 230 × 23 × 5m, the main deformation of objects to the settlement, not only for the future force calculation lock floor to provide data to improve the accuracy of the , but also easy to detect anomalies and take measures to ensure that the project material deformation measurement point of order "and the Ministry of Transportation," Water Transportation Engineering Survey norms "in the provisions of the settlement observation, combined with solutions of Taiwan second-tier ship lock project specific characteristics, we choose Deformation measurement of two standards as the work of this item settlement observation precision index, shown in Table 1.

Settlement observation is a high precision lock engineering survey work equipment, laid routes, observation methods and the quality of personnel and other aspects will affect the accuracy of observational data. In the measurements we have chosen to S1 level in Switzerland LeicaNA2/GPM3 precision leveling, with the indium-foot steel standard operating on the Provincial Bureau of Surveying and Mapping Department of the apparatus of the identification of indicators of the technical appraisal, in the operation during which we repeatedly instrument i, c. difference of check, for the observations provided technical assurance.

3.2 Observation 3.2.1 benchmarks laid line, work-basis-point benchmarks set by the original rating level point of the surveyed area (design departments) BM (33.226m), G2 (32.652m) composition, The two elevation data measured by multiple joint check, height difference error is less than 1.0mm. And the two benchmarks are located in the brake line management area is more remote places, is the first-line gate during the construction period (1958 ~ 1961) is set, the points are stable and reliable. We observed better-BM as the main point, G2 as a calibration point. The use of the south side of the original line lock (second-tier works area outside the gate) gate wall, a settlement of nails (A9) as a working basis points, with BM, G2 to form a closed loop, testing the accuracy of initial data.

3.2.1 laid on the observation points, the next gate in the first paragraph and the chamber are in side-dock-type pier and construction of a wide bottom seam laid 8 to each end of the settlement within 24 observation points nails; chamber 14 Fu wall segments are in lock wall at both ends of the floor laid four nails into account the settlement of 56 observation points; settlement nail making use of 40cmФ18 rebar welded copper top round hat hemisphere processed, buried, when coupled with oblique bars welded to the end of plate surface layer and vertical reinforcement, the top highlight the concrete surface, about 1.5 ~ 2.0cm in order to guarantee points are solid.

A9 by the working point to the observation points along the line of basic pond perimeter gates set on undisturbed soil, in the middle switch all the laid-point measurement of pile, using 50 ~ 100cmФ20 rebar into the soil surface, 20 ~ 30cm thick concrete poured into the gate pond slope segment , in addition to using the same pre-set switch point, the station location of the mirror frame is also laying 30cm thick concrete, in order to ensure the stability of the instrument for observation.

Throughout the observation line from BM, A9, and 14-2,12-4,10-2 in 11 observation points to form a closed loop overall length of 1. 32km, 36 stations, not the other observation points on the route, by observation points near the fixed observation.

3.3 Observation methods and precautions used in this settlement observations precise geometric leveling method, observation during the error control and data processing within the industry, according to the national "material deformation measurement point of order" in the regulations.

Observations carried out settlement process, it should be noted several issues: (1) Each observation shall be subject to the "four fixed" principles, namely: observation instruments and standards of the gauge fixed; observation officer fixed; observation line fixed; observing the environment and conditions for basic the same.

(2) Level i angle is a change in the value of each job before the right angle i checked, if it i angle greater than 10 seconds, should be tested promptly corrected.

(3) emplacement of observation path, around-the-horizon does not exceed 40m, around-the-horizon difference of not more than 1. 0m, to control the i angle errors, while increasing the clarity of observation.

(4) The observation time and the environment: not 1 hour before and after sunrise, noon to observe, not to high winds or fog in the case of observations.

(5) In order to ensure stability of the standard bubble-foot center, self-supporting with some simple standard-foot pole, so fast and stable member of Rotary-foot vertical ruler to improve observing efficiency.

3.4 The observation period is based on sub-floor lock construction, in order to grasp the load after the initial observations, in each section after the final setting of concrete floor poured, it immediately started the initial observation, so different subsidence backplane The initial observation date of observation points is not the same.

For the material deformation observation period, the measurement of norms, a point of order failed to make uniform provisions, we have the same type of locks based on past experience, combined with chamber wall, this project uses a gantry support for large formwork concrete pouring reach the peak of the construction plan, an analytical basis for load situation, and adopt the following observation period: 20 days early phase of construction, pre-closure hinge to hinge closure during the 10 days after the closure hinge to the observation point moved to the chamber wall, measured at the top of 30 days.

Locks during the construction of the main objects, as encountered special circumstances (there is a greater return to fill with ground water level changes, floor or wall cracks, uneven settlement joint on both sides showed a larger settlement, etc.) should be immediately carried out daily or a few days once a continuous observation of the timely provision of observation data, to ensure the material security.

4 settlement observation results

From May 2000 to January 2002, a total of 40 times to complete settlement of observation (June 26, 2001 after the shift to the chamber wall, measured at the top of observation), closed loop closed difference of the height difference -0. 3 ~ +1 . 5mm between the level of measurement accuracy to meet the second requirement. Settlement observation results of the data in Table 2.

5 Conclusions and experience

(1) The observational data indicate that the entire construction phase of this project based on the amount of subsidence of the changes in volume and rebound and construction sequence, ground load on the size, construction schedule, and groundwater levels are closely related to the situation and so on.

(2) The settlement of observational data to reflect the actual settlement amount of the construction phase, it is difficult to provide the theory and design department set aside settlement consistent with theoretical calculations assume that the main reason is the above-mentioned conditions are changing conditions and access to large, the calculation can not consider the construction period of kinds of dynamic factors, while complex geological conditions. Although the present theoretical calculations take into account soil consolidation process, the foundation is calculated as a visco-elastic model, but calculated parameters varied with the different qualities of clay and hard to the right selection, it is only through on-site observation, use of anti-analysis to determine the calculation of parameters, in order to provide effective data for the design.

(3) The total settlement volume associated with the initial observation, so the accuracy of the initial observation is extremely important for the initial observation points for each observation must be used initially the average of two consecutive observations.

(4) The lock works settlement observation is a very complicated job, technically demanding, it will take hard work. Chamber wall backfill construction of part of the observed line may be temporarily adjusted, and fails to reach a fixed as ever, which is the main reason affecting the accuracy of observation. Use of total station at a fixed measuring stations and mirror the high case, by trigonometric leveling method to replace the geometric standards of conduct settlement observation can reduce labor intensity, but can meet the required accuracy is worth in the future to study the construction of Lock .